DE102023109686A1 - heater with an air guiding device - Google Patents

Abstract

The invention relates to a heating device (1) with a premixing burner (3) designed for connection to a combined exhaust gas line (10) and combustion air line (4) comprising an air guide device (13) designed to supply combustion air to at least one component (2, 5, 7, 6, 12) of the heating device (1) that is to be cooled. This advantageously enables cooling of components (2, 5, 7, 6, 12) of the heating device (1), which is particularly advantageously accompanied by an increase in the efficiency of the heating device (1) by additional heating of the combustion air.

Description

The invention relates to a heater with an air guiding device.

Premixing heaters usually have a burner, which is fed with a mixture of fuel gas and combustion air and burns it. The combustion products can be fed to an exhaust system via an internal exhaust duct of the heater. A combined line for the exhaust system and combustion air supply is often used, with two pipes arranged concentrically and an inner pipe forming the exhaust system and an outer pipe forming the combustion air supply. The waste heat from the exhaust gas can advantageously be transferred to the combustion air, thus increasing the efficiency of the heater. Such a combustion air supply combined with the exhaust system is used, for example, in the GB 947 114 A described.

In addition, modern heaters are often very compact and designed as wall-mounted heaters. The compact design can make thermal decoupling of the individual components of the heater more difficult. For example, the waste heat from a combustion chamber in which the burner is located can heat up neighboring components, which can reduce their service life and thus the service life of the heater.

The object of the present invention is to at least partially alleviate the problems described with reference to the prior art and in particular to propose a heating device which combines the advantages of compactness, i.e. a small design, and very good thermal decoupling of the components and also has high energy efficiency.

Last but not least, the invention should be easy to implement and at least partially retrofittable to existing systems. The complexity and compactness of a heating device should also not be reduced by the invention.

These objects are achieved by the features of the independent patent claim. Further advantageous embodiments of the solution proposed here are specified in the independent patent claims. It is pointed out that the features listed in the dependent patent claims can be combined with one another in any technologically reasonable manner and define further embodiments of the invention. In addition, the features specified in the patent claims are specified and explained in more detail in the description, with further preferred embodiments of the invention being presented.

A heater with a housing and a premixing burner arranged therein contributes to this, which is designed for connection to a combined exhaust gas and combustion air line and comprises at least one air guiding device in the housing. The at least one air guiding device is designed to supply supplied combustion air to at least one component of the heater that is to be cooled.

The heater can be a gas heater. This can comprise a conveying device designed as a blower, in particular a blower that can convey a mass flow (or volume flow) of combustion air or a combustion mixture of fuel (combustion gas) and air. The combustion air can be supplied via a combustion air supply. A gas valve is set up to add a mass flow (or volume flow) of combustion gas corresponding to a predetermined combustion air ratio. The combustion mixture formed can then be supplied to a burner of the heater via a mixture channel and burned there. Since the burner receives a mixture of combustion air and combustion gas, it is referred to as a "premixing" burner. The heater can form a pneumatic or electronic gas-air connection for this purpose.

The heater can be designed or constructed to be connected to a combined exhaust and combustion air line. The exhaust line and combustion air line are "combined" in particular when they are at least partially connected or integrated with one another. A combined exhaust line and combustion air line is present in particular when they are mounted at the same point on the housing, in particular at a common housing opening. A combined exhaust line and combustion air line is present in particular when waste heat from the exhaust line can be made available inside the combustion air line.

The burner of the heater can be arranged in a combustion chamber that is housed in the housing of the heater. This can have a burner door through which the combustion mixture of fuel gas and combustion air can be fed into a burner cavity of a burner that is also arranged on the burner door. In addition, other components, such as sensors or electrodes for flame monitoring, can be arranged on or in the burner door.

The heater can also be set up to burn hydrogen or a hydrogen-containing mixture of fuel gases. Due to a significantly higher flame speed, flashbacks are more likely to occur when hydrogen is burned. To counteract this, the heater's burner can have a flame arrester, for example arranged in a burner cavity at a distance from a burner surface. A flame arrester can prevent flashbacks (reignitions), i.e. flame spread in the direction of the heater's mixture channel.

A combined exhaust and combustion air line is characterized by a parallel discharge of the exhaust gases and supply of the combustion air. For example, the combined exhaust and combustion air line can have two concentrically arranged pipes, of which an inner pipe is the exhaust line and an outer pipe is the combustion air line, so that the combustion air flows around the exhaust line and a heat flow from the exhaust gas to the combustion air is established. Further use of the residual heat of the exhaust gas can advantageously increase the energy efficiency of the heater.

The heater can in particular be a wall-mounted heater, having a geodetic connection on the top for the exhaust system (exhaust pipe) and combustion air supply (combustion air pipe). Additional connections are often provided on the top of the housing, for example those of a heating circuit, a power supply and a gas supply.

By means of the invention, combustion air can be directed to the components of the heater that are to be cooled by means of an air guide device in order to cool them. The flow of combustion air can advantageously promote or specifically set forced convection for heat dissipation of the components to be cooled. This makes it possible to significantly improve the thermal decoupling of the components from one another. In addition, the energy efficiency of the heater can be further increased because the waste heat from the components is fed into the combustion process.

Preferably, a single air guiding device is provided. The air guiding device can be arranged adjacent to the combined exhaust gas line and combustion air line inside the housing. It is possible for the air guiding device to be arranged at least partially directly adjacent to an upper part and/or a side part of the housing. It is possible for the air guiding device to be partially formed by an upper part and/or a side part of the housing. It is possible for the air guiding device to form grooves, channels, openings, etc., by means of which a precise supply of combustion air to the at least one (functional) component of the heater to be cooled, which is also positioned inside the housing, is made possible. Preferably, the air guiding device itself is passive, i.e. in particular does not comprise any moving components that cause the supply or forwarding of combustion air. The air guiding device can essentially (only) consist of flow guide surfaces, whereby (smaller) sections for supporting and/or attaching to the housing or its components can be provided if necessary. The air guiding device can be designed in one piece.

The components to be cooled are in particular (directly and/or indirectly) connected to the combustion chamber in a heat-conducting manner. The component to be cooled can itself be part of the combustion chamber or be connected to the internal burner cavity. In particular, the component can have electrical and/or electronic components and/or connections. The component can be responsible for the functionality of the burner/heater. The component to be cooled is in particular positioned in the heater in such a way that it could possibly reach an increased (possibly predetermined) limit temperature during operation due to waste heat from the combustion chamber, thereby counteracting the cooling flow generated by the air guiding device. The cooling flow generated by the air guiding device can (possibly preset and) flow selectively to several components with varying strengths, e.g. depending on the expected temperature load and/or its intensity with the heat source. It is possible that the cooling flow is directed at a (or the entire) section of the component and/or its fastening that faces the interior of the housing.

• - Sensoren des Heizgerätes, insbesondere ein Massestromsensor, beispielsweise in der Zuführung Verbrennungsluft, Sensoren zur Flammenüberwachung, wie ein UV-(Ultraviolett-) oder Temperatursensor, ein Glühzünder (auch als Hot-Surface Ignitor bezeichnet)
• - eine Flammenüberwachung oder Teile davon,
• - Elektroden, wie insbesondere Zünd- oder Ionisationselektroden,
• - eine Fördereinrichtung des Heizgerätes, häufig als Gebläse ausgebildet,
• - das Gasventil, und
• - eine Brennertür.

According to one embodiment, the at least one component to be cooled can be selected from the following group:

• - Sensors of the heater, in particular a mass flow sensor, for example in the combustion air supply, sensors for flame monitoring, such as a UV (ultraviolet) or temperature sensor, a glow igniter (also known as a hot-surface ignitor)
• - a flame monitoring system or parts thereof,
• - Electrodes, such as in particular ignition or ionization electrodes,
• - a conveying device of the heater, often designed as a fan,
• - the gas valve, and
• - a burner door.

According to one embodiment, the air guiding device can supply the mass flow of combustion air to the components to be cooled as required. In this case, "as required" means that the air guiding device is designed in such a way that the mass flow of combustion air is divided up and supplied to the components according to their cooling requirements. For this purpose, the air guiding device can comprise air guiding elements or ducts. The cooling requirements of the components of the heater are known or can be easily determined in tests. It is possible that the flow behavior of the combustion air changes during operation, whereby it can be provided that with a change in the volume flow, other flow paths are formed on/at the air guiding device and thus, if necessary, different components are supplied with a cooling flow with varying intensity.

The air guiding device can be adapted in particular to the specific heater and the positions of the components to be cooled within the housing of the heater.

The air guide device can be made of any material that can withstand the temperatures occurring in the heater. This could in particular be plastic or a metal, for example aluminum. Aluminum has a very high thermal conductivity and can thus quickly dissipate heat radiation absorbed by the air guide device. The air guide device can be manufactured, for example, using 3D printing or an injection molding process.

According to one embodiment, the air guiding device can have a funnel shape or bell shape, with an upwardly directed narrow side of the air guiding device being connected to the combustion air line and a wide side of the air guiding device causing the combustion air to be supplied to the components to be cooled. For this purpose, the wide side can at least partially enclose the components to be cooled. The partial enclosing can in particular cause a targeted flow of air to the components to be cooled. Described differently, the air guiding device can also be a three-dimensional structure with a connection to a combustion air line arranged on the top in the installed position.

According to one embodiment, the air guiding device can be designed in particular to flow to and cool the burner door of the combustion chamber of the heater. It has been found that the temperature of the burner door can also have a direct influence on components connected to the burner door, in particular on the temperature of the burner, the flame arrester of the burner and sensors or electrodes arranged in the burner door.

In particular, the use of an air guiding device is proposed in order to cool components of the heater by means of combustion air supplied to a heater. The air guiding device can in particular be funnel-shaped and can cause combustion air to flow in a targeted, demand-based manner to components of the heater that are to be cooled.

The explanations for the heater can also be used to further characterize its use, and vice versa.

A heater and a use of an air guiding device are therefore specified here, which at least partially solve the problems described with reference to the prior art. In particular, the heater and the use at least help to avoid high temperatures of components of a heater and thus increase the service life of the component and thus of the heater. In addition, the energy efficiency of the heater can be further increased by transferring waste heat from the components to the combustion air.

As a further advantage, the invention can be implemented with no or only minor structural changes to a heater. All that is required is an air guiding device, which is specific to the heater type. Retrofitting the invention to existing heating systems therefore also appears possible and sensible.

• 1: ein hier vorgeschlagenes Heizgerät, und
• 2: eine Darstellung einer Luftleiteinrichtung im Heizgerät.

The invention and the technical environment are explained in more detail below with reference to the accompanying figures. It should be noted that the invention is not intended to be limited by the exemplary embodiments given. In particular, unless explicitly stated otherwise, it is also possible to extract partial aspects of the facts explained in the figures and combine them with other components and findings from the present description. In particular, it should be noted that the figures and in particular the size relationships shown are only schematic. They show:

• 1 : a heater proposed here, and
• 2 : a representation of an air guiding device in the heater.

1 shows an example and schematically a heating device 1 proposed here. This can supply combustion air via a combustion air line 4 through a conveyor device 2 and add a gas from a gas supply 16, for example hydrogen, to the sucked-in mass flow of combustion air via a gas valve 5. The combustion mixture 17 of fuel and combustion air can now be fed via a mixture channel 11 to a burner 3 arranged in a combustion chamber 8. The combustion products can be fed via an exhaust channel 9 from the combustion chamber 8 to an exhaust line (exhaust system) 10. The burner 3 is attached to a burner door 6, in which a flame monitor 12 can also be arranged, for example a UV sensor. The UV sensor can be arranged outside the combustion chamber 8, protected from the high temperatures of the burner 3. The heating device can also have a regulating and control device 7. The heating device 1 can be set up to burn hydrogen as fuel.

Please note that the presentation in accordance with 1 is purely schematic and does not allow any conclusions to be drawn about the position or arrangement of the components in the heater or in relation to one another. In particular, the combustion air line 4 can run at least partially parallel to the exhaust gas line 10.

2 shows, by way of example, a heating device 1 with an air guide device 13. This can be connected to the combustion air line 4 on the top, geodetically or in relation to an installation position of the heating device 1, so that the combustion air sucked in by the conveyor device 2 via an air inlet 19 of the silencer of the air supply flows through the air guide device 13. In addition, further connections can be provided on the top of the heating device 1, for example a flow and return of a heating circuit 14. The 2 further illustrates how the air guiding device 13 distributes the intake combustion air in a targeted manner and directs it to components. These are, for example, a first air flow 20 to an electrode 18 to be cooled, a second air flow 21 to the flame monitor 12 (UV sensor), a third air flow 22 to a glow igniter 26 and a fourth air flow 23 to the gas valve 5. The targeted flow of combustion air onto the components can increase the forced convection and thus improve the cooling of the components.

3 shows, by way of example and schematically, the area of a burner door 6 of the heating device 1, to which the burner 3 is connected and in the immediate vicinity of which the glow plug 26 and the electrode 18 are arranged. A fifth air flow 24 can flow around the burner door 6 so that cooling of the same and adjacent components (glow plug 26, electrode 18 (e.g. ionization electrode) and burner 3) can be achieved by heat conduction 25, since components arranged in the combustion chamber 8 cannot be directly flown against. It is noted here for the sake of clarity that the naming of specific components is of an exemplary nature.

As a precaution, it should be noted that the numerals used here ("first", "second", ...) primarily serve (only) to distinguish between several similar objects, sizes or processes, and in particular do not necessarily specify a dependency and/or sequence of these objects, sizes or processes. If a dependency and/or sequence is required, this is explicitly stated here or it is obvious to the person skilled in the art when studying the specifically described design. If a component can occur multiple times ("at least one"), the description of one of these components can apply equally to all or part of the majority of these components, but this is not mandatory.

list of reference symbols

1

heater

2

conveyor system

3

burner

4

combustion air line

5

gas valve

6

burner door

7

control unit

8

combustion chamber

9

exhaust duct

10

exhaust pipe

11

mixture channel

12

flame monitoring

13

air guiding device

14

heating circuit

15

Housing

16

gas supply

17

combustion mixture

18

electrode

19

air intake silencer

20

first air flow

21

second air flow

22

third air flow

23

fourth air flow

24

fifth air flow

25

heat conduction

26

glow plug

QUOTES INCLUDED IN THE DESCRIPTION

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

Cited patent literature

• GB 947114 A [0002]

Claims (6)

Heating device (1) with a housing (15) and a premixing burner (3) arranged therein and designed for connection to a combined exhaust gas line (10) and combustion air line (4), comprising at least one air guiding device (13) in the housing (15) which is designed to supply combustion air supplied via the combustion air line (4) to at least one component (2, 5, 7, 6, 12, 18, 19, 26) of the heating device (1) to be cooled. heater after claim 1 , wherein the at least one component to be cooled is provided in the housing (15) and is selected from the following group: - sensors, - flame monitoring (12), - electrodes, - conveying device (2), - gas valve (5), and/or - burner door (6). Heating device (1) according to one of the preceding claims, wherein the at least one air guiding device (13) supplies the mass flow of combustion air to the at least one component (2, 5, 7, 6, 12, 18, 19, 26) to be cooled as required. Heating device (1) according to one of the preceding claims, wherein the at least one air guiding device (13) is shaped such that the supplied mass flow of combustion air flows against the outside of the burner door (6) of the heating device (1). Heating device (1) according to one of the preceding claims, wherein the combined exhaust gas line (10) and combustion air line (4) is geodetically connected to the upper side of the heating device (1) and the air guiding device (13) has a funnel shape and/or bell shape, wherein an upwardly directed narrow side of the air guiding device (13) is connected to the combustion air line (4) and a wide side of the air guiding device (13) partially encloses the at least one component (2, 5, 7, 6, 12, 18, 19, 26) to be cooled. Heating device (1) according to one of the preceding claims, wherein the air guiding device (13) was produced by means of 3D printing.

Images