DE102021112468A1 - Burner for a heater and use of a spring element for a burner - Google Patents

Abstract

Burner (1) for a heating device, having a burner body (2) and a burner door (3) between which a seal (4) is arranged, with an electrical connection by means of a contact device between the burner body (2) and burner door (3) in the area of a Gas supply (10) from the burner door (3) to the burner body (2) and/or within the seal (4) arranged between the burner body (2) and the burner door (3).

Description

The invention relates to a burner for a heating device and a structure of a burner.

In heaters with a pneumatic or electrical gas connection, an ionization signal from the flame can be used to monitor them. In particular in connection with an electrical gas network, an ionization signal from the flame can also be used to regulate the mixture composition of the gas network.

In prior art heaters, the ionization signal of the flame is often measured between a gas exit region of the burner, referred to herein as the burner body, and an ionization electrode. A measuring circuit can be provided for this purpose, which is suitable or set up for flame monitoring. For example, an AC voltage source with a high output resistance can initially supply an AC voltage essentially without a DC component to an ignition electrode (or ionization electrode) and the counter-electrode (torch body, electrical ground). When a flame occurs between the two components, the voltage between the rectifier effect of the flame only drops in one half-wave, so that an AC voltage with a negative DC component is present at the input of the evaluation electronics, which becomes the desired ionization signal in the evaluation electronics and is converted into an analog/ converted to a digital converter and then further processed. This arrangement forms a preferred detector for flame monitoring, which then supplies an ionization signal when a flame is present, the ionization signal also having a typical profile from which, for example, the beginning of the physical lifting of the flames from gas outlet openings can be detected, so that a shutdown can also be beginning of instability due to gas velocities that are too high and/or lambda (A) values that are too high.

The electrical ionization signal is transmitted via the mechanical connection of the burner body, for example in a burner door. The mechanical connection can be a screw connection, for example. However, it has been shown that the ionization signal may not be measurable with long-term stability or error-free accuracy. This means that it is no longer possible to monitor the flame with sufficient reliability and/or in the case of an electrical gas network, shifts can also occur in the control of the mixture composition, which is dependent on the ionization signal. As a result, the heater can usually be switched off as a safety measure, which in turn can necessitate costly repairs.

Proceeding from this, it is the object of the invention to propose a burner for a heating device which at least partially overcomes the problems of the prior art described. In particular, the burner should enable reliable and long-term stable transmission of the ionization signal.

In addition, the invention should at least not significantly increase the complexity of a heating device and/or require only minor structural changes to a heating device and enable simple integration into an existing production process.

These objects are solved by the features of the independent patent claims. Further advantageous refinements 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 meaningful manner and define further refinements 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 configurations of the invention being presented.

A burner for a heating device contributes to this, having a burner body and a burner door between which a seal is arranged, with an electrical connection by means of a contact device between burner body and burner door in the area of the gas supply and/or within the seal arranged between burner body and burner door.

The heater can be any heater that requires an electrically conductive connection between the burner door and the burner body, in particular a heater with flame monitoring using an ionization signal. As a rule, flame monitoring is carried out by means of an ionization signal in heaters with an electrical or pneumatic gas connection.

A burner, also known as a heat generator, produces heat by burning a combustible gas. For this purpose, the gas is fed into a burner body, from which it exits through openings and burns in a combustion chamber. Exhaust gas produced during combustion can usually be removed via at least one heat exchanger, which transfers the heat to a heat transfer medium, can be fed to an exhaust system.

Gas here generally refers to a combustible mixture of air and a fuel, in particular natural gas, petroleum gas or hydrogen.

A burner body refers here to a flame-generating element of the burner, which usually has an internal cavity for gas supply. Gas supplied via (radial or lateral) openings can exit and burn from the cavity of the burner body via a large number of openings in the burner body.

A burner door designates a part of the burner or the burner housing which is firmly connected to the burner body and has a gas supply which is connected gas-tight to the cavity of the burner.

Burner door and burner body can be connected via a flange connection, which can be fixed with fastening elements, in particular screws or rivets, passed through the flange connection. The flange connection can often have a seal to prevent gas leakage.

In particular, it is proposed here to set up a (separate) electrical connection between the burner body and the burner door, which is provided (exclusively) for the measuring circuit for determining the ionization signal. In particular, it is (also) avoided that this electrical connection is exposed to considerable tensile loads and/or that the contact conditions change significantly due to high temperatures and/or temperature fluctuations.

Accordingly, the contact device can be a (separate) component whose primary or essential function is to establish or maintain an electrical connection between the burner body and the burner door.

The positioning or attachment of a contact device in the area of a gas feed line from the burner door to the burner body means in particular that the contact device extends at least partially into this gas line or is even predominantly or completely arranged there. For example, the contact device can be arranged or fixed in at least one section of the burner door and/or burner body that delimits the respective gas flow. It is possible for the contact device to be connected to only one gas-carrying section of the burner door and one gas-carrying section of the burner body. It is possible for the contact device to protrude into the gas duct from a transition or sealing area of the burner door and burner body and then rests upstream or downstream on a section of the gas duct or is fixed. A seal (e.g. surrounding the gas duct) can be provided in the transition or sealing area of the burner door and burner body, which seal may also be made of an electrically non-conductive material. A contact device can therefore also be formed within this seal or extending through this seal.

By arranging an electrical contact device in the area of the gas supply or the seal as proposed here, the contact device and its contact areas with the burner body and/or burner door can advantageously be prevented from being exposed to the corrosive conditions in the combustion chamber. In this way, a long-term stable electrical connection can be created.

The designation within a seal is to be understood in particular to mean that the seal at least partially encloses the contact device, so that the contact device cannot have any (physical) contact with the combustion chamber.

The designation within the gas supply means in particular that the contact device only comes into contact with the supplied gas and has no (physical) contact with the combustion chamber.

The seal itself may include (fully or partially) the contact means. It goes without saying that the material of the seal should be sufficiently heat-resistant for the temperatures occurring in the area of the connection between the burner body and the burner door. The seal can be a paper seal, for example, into which electrically conductive metallic threads are incorporated. Alternatively or cumulatively, a (non-electrically conductive) seal can also be at least partially provided with an electrically conductive coating, doped with an electrically conductive material (e.g. by means of a powdered electrically conductive material) and/or impregnated, so that this creates an electrically conductive contact of the burner door and burner body.

The contact device can include a cable with (at least) one connecting element. The cable can be permanently connected to the burner door and/or the burner body, for example by soldering, welding and/or a screw or rivet connection. It goes without saying that this fixed connection is electrically conductive. About the (single) connector may be electrically connected to a corresponding connector in either the burner door or the burner body, which connector may be any releasable connection that provides an electrically conductive connection. In particular, a plug connection is proposed. This refinement can be implemented easily and can ensure a very long-term stable electrical connection. The cable can have two connecting elements that can be connected to corresponding connecting elements on the burner body and burner door.

The contact device can include at least one spring element, which brings about an electrically conductive connection between the burner door and the burner body by means of a spring force. Advantageously, an electrically conductive connection based on spring force does not require any (rigid or fixed) connection points for the connection and can also excellently compensate for displacements caused by the expansion of different materials (e.g. burner body and burner door) with different expansion coefficients.

The spring element can be fixed to (either) the burner door or the burner body. Here too, a fixed connection can be an electrically conductive connection, for example by soldering, welding and/or a screw or rivet connection. According to a preferred embodiment, the spring element can also be firmly and electrically conductively connected to the burner body or burner door by means of a fastening element of the flange connection. Due to its spring force, the spring element presses on the burner door or burner body and thus creates an electrically conductive connection. It goes without saying that the fixed connection (or the fixed connection established by means of the fastening element) is to the burner door and the electrically conductive connection is established by means of spring force on the burner body or vice versa. This configuration is particularly easy to implement, so no structural changes to the burner body and burner door are necessary, particularly when the spring element is fastened by a fastening element of the connection between the burner body and the burner door.

It goes without saying that a plurality or even a multiplicity of spring elements are preferably provided in order to create an electrically conductive connection with a high level of reliability through redundancy and also to achieve as equal a distribution as possible of the spring forces that occur.

A spring element, which is firmly and electrically conductively connected to the burner body or the burner door by means of a fastening element of the flange connection, can have an elongated hole (e.g. not a circular but an elongated, slot-like recess) for fastening to the fastening element. When the spring element is in the fastened state, the elongated hole can be aligned radially with respect to the gas supply line, so that the spring force for an electrically conductive connection can be adjusted by moving the spring element within the elongated hole. This configuration advantageously offers very good adjustability of the electrically conductive connection between the burner body and the burner door, without the need for structural changes to the burner body or the burner door. In addition, this configuration can be easily integrated into an existing production process.

The spring can be a spring subjected to bending stress, for example a clamp, leaf spring or disc spring.

The spring element can also be designed as a crown or ring that can be integrated into the connection between the burner body and the burner door (in the transition or sealing area). The rim or ring could have a large number of spring elements, for example flexible springs distributed over its circumference, which cause an electrically conductive connection of the burner door and burner body by bridging the seal.

The burner door or the burner body can provide a receptacle for the spring element, for example a depression or a bead, at a point at which the spring element produces an electrically conductive connection by means of spring pressure. In this way, the assembly of the burner body and burner door can advantageously be simplified because a mechanically stable connection can already be produced by the spring elements and the task of the fastening elements is then to press the seal.

The spring element or the contact device can be a (possibly one-piece) partial area of the burner body or the burner door. In particular, the spring element can be a sheet metal tongue, for example, which creates an electrically conductive connection between the burner body and the burner door by means of a bending force. The sheet metal tongue could, for example, be a part of a collar of the burner body or burner door in the gas supply or also a part of the flange of the burner body. The sub-area of the sheet metal collar could in particular be produced by stamping or another separation method. This refinement can also be advantageously implemented without any significant structural changes to the burner body or burner door.

The spring element can be a pressure-loaded spring, in particular a spiral spring, which causes an electrically conductive connection between the burner body and the burner door by means of spring pressure. The compressively stressed spring can in particular be arranged in a (separate) opening or corresponding openings, eg in the manner of a blind hole, in the burner body and/or burner door and produce an electrically contacting connection through a (separate) cutout in the seal. Particularly preferably, the compression-loaded spring, in particular a spiral spring, can have caps or covers made of an electrically conductive material at its ends in order to increase the contact surface and thus improve the electrical contacting.

The spring element can be arranged in the area of a fastening element for connecting the burner body and burner door to one another. In particular, the spring element can be an annular spring element which can be arranged around a fastening element in a fastening recess in the seal between the burner body and the burner door.

The spring element can be a collar of the gas supply, in particular of the burner body, which is shaped in such a way that a radially outwardly acting spring force of the collar brings about an electrically conductive connection. The collar can have a number of tongues, projections, etc. or recesses distributed over its circumference in order to create a number of electrically conductive contact areas.

The contact device can be an inlay (insert, etc.) made of electrically conductive material, which is arranged in a (fastening) recess in the area of a fastening element for connecting the burner body and burner door or is arranged in a (separate) recess in the seal between fastening elements . The inlay can be made of a conductive and heat-resistant material, such as graphite. Only a single inlay is preferably provided.

According to a further aspect, a heating device is also proposed, having a burner proposed here. The heater is in particular a gas heater that is set up to burn a fuel gas with the supply of ambient air and to heat thermal energy, for example to heat water as a heat carrier of a heating circuit or to provide it in a hot water supply. In particular, the heater can be a gas condensing boiler. The heater generally has a combustion chamber and a delivery device that delivers a mixture of fuel gas and combustion air into a combustion chamber. The combustion products can then be discharged through an exhaust system. In particular, the heater can monitor the flame by means of an ionization signal in conjunction with an electrical or pneumatic gas network.

According to a further aspect, the use of a spring element is proposed in order to bring about an electrically conductive contact between a burner door and a burner body. According to a further aspect, the use of a (partially) electrically conductive seal is proposed in order to bring about an electrically conductive contact between a burner door and a burner body.

A burner, a heating device and the use of a spring element are thus specified here, which at least partially solve the problems described with reference to the prior art. In particular, the burner, the heater and the use at least contribute to creating a long-term stable electrical connection between a burner door and a burner body, as a result of which the operational reliability of the heater and its service life can be significantly extended.

In addition, the invention can easily be implemented on existing burners of a heating device and can be easily integrated into existing production processes.

• 1: einen hier vorgeschlagenen Brenner mit einem Kabel und einem Verbindungselement,
• 2: einen hier vorgeschlagenen Brenner mit einem Federelement,
• 3: einen hier vorgeschlagenen Brenner mit einem biegebeanspruchten Federelement,
• 4: einen hier vorgeschlagenen Brenner mit einem druckbeanspruchten Federelement im Bereich eines Befestigungselementes,
• 5: einen hier vorgeschlagenen Brenner mit einem Inlay als Kontakteinrichtung, und
• 6: einen hier vorgeschlagenen Brenner mit einem Kragen als Kontakteinrichtung.

The invention and the technical environment are explained in more detail below with reference to the attached figures. It should be pointed out that the invention should not 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 to combine them with other components and findings from the present description. In particular, it should be pointed out that the figures and in particular the proportions shown are only schematic. Show it:

• 1 : a torch proposed here with a cable and a connector,
• 2 : a burner proposed here with a spring element,
• 3 : a burner proposed here with a spring element subjected to bending stress,
• 4 : a burner proposed here with a compressively stressed spring element in the area of a fastening element,
• 5 : a burner proposed here with an inlay as a contact device, and
• 6 : a torch proposed here with a collar as a contact device.

1 shows an example and schematically a burner 1 of a heater. The burner 1 can have a burner body 2 and a burner door 3, the burner body 2 being able to be fastened to the burner door 3 by means of fastening means 5, designed here as screws. A seal 4 around a gas supply line 10 can be provided in order to ensure a gas-tight connection between the burner body 2 and the burner door 3 . For the connection of burner body 2 and burner door 3, a flange 6 can be provided, through which the fastening means 5 can be passed. The burner door 3 can have a gas supply 10 which is connected to a cavity in the burner body 2 .

An electrically conductive connection between burner body 2 and burner door 3 can be effected with a cable 7 having a connecting element 8, designed here as a plug. During the assembly of burner door 3 and burner body 2 , cable 7 can be guided through seal 4 and connected to a corresponding connecting element 9 . Connecting element 8 and corresponding connecting element 9 are designed here as plugs and couplings and realize a long-term stable electrically conductive connection, which is also protected from the corrosive conditions of the burner chamber by an arrangement in the gas supply line 10 .

2 shows - accordingly 1 - By way of example and schematically, a burner 1 with a burner body 2 and a burner door 3. An electrically conductive connection between the burner body 2 and the burner door 3 can accordingly be realized by means of a spring element 11. The spring element 11 can be a compression-loaded spring, such as a spiral spring, which can be introduced into an opening 12 in the burner door 3 . The opening 12 can be designed as a blind hole. When the burner body 2 and burner door 3 are in the assembled state, the spring element 11 can penetrate the seal 4 through a recess 13 and exert pressure on the burner body 2, in particular the flange 6, through its compressive force and thus produce an electrically conductive connection. In order to ensure reliable electrical contact between a spiral spring and burner body 2 and/or burner door 3, electrically conductive caps or covers can be provided at the ends of the spiral spring, which increase the contact surface and thus ensure reliable electrical contact.

3 shows - accordingly 1 and 2 - By way of example and schematically, a burner 1 with a burner body 2 and a burner door 3. Illustrated here is an embodiment in which the spring element 11 is a bending-stressed spring. The spring element 11 , designed as a spring subjected to bending stress, can be firmly attached to the torch body 2 , in particular to the flange 6 .

In the contact area of a spring element 11 and the burner door 3, a receptacle 19 of a spring element 11 can be provided, for example designed as a recess, bead or the like. Mountings 19 of the spring elements 11 in the burner door 3 can facilitate assembly, in that the mountings 19 already fix the burner body 2 to the burner door 3 and the fastening means 5 cause the seal 4 to be pressed in a gas-tight manner.

According to an alternative embodiment, the spring element 11 designed as a spring subjected to bending stress can also be inserted between the seal 4 and the flange 6 during the assembly of the burner door 3 and the burner body 2 and pressed against the flange 6 by the fastening means 5, so that an electrically conductive connection arises.

In an alternative or cumulative configuration, the spring element 11 designed as a spring subjected to bending stress can also have an elongated hole through which a fastener 5 can be guided during assembly, with the elongated hole enabling the spring element 11 to be displaced in a displacement direction 15 which in turn, an adjustability of the (bending) spring force of the spring element 11 on the burner door 3 in the area of the gas supply 10 is made possible.

According to an alternative embodiment, the spring element 11 designed as a spring under bending stress can be designed as a ring with a plurality of spring elements 11 designed as a spring under bending stress, the ring being able to be inserted between the seal 4 and the flange 6 during assembly. The ring can also have an inner and outer radius and corresponding holes through which the fastening means 5 can be passed through the spring element 11 designed as a ring.

The or the bending stressed spring elements 11 according to 3 can be passed through separate recesses in the seal 4 or through the inner opening of the seal 4 for the gas supply.

4 shows a burner 1 proposed here with a compressively stressed spring element 11 in the region of a fastening means 5. For illustration contains the 4 on the right side a plan view of a seal 4.

According to the 4 In the embodiment shown, a pressure-loaded spring element 11 , embodied for example as a disc spring or spring ring, can be arranged in the region of a fastening means 5 . For this purpose, the seal 4 can have an enlarged recess 13 for a fastener 5 .

Alternatively or cumulatively, corresponding pressure-loaded spring elements 11, for example designed as plate springs or spring washers, can also be arranged in areas of the seal 4 between the recesses 13 for the fastening means 5.

5 shows a burner 1 proposed here with an inlay 14 as a contact device. An inlay 14 can be designed in the area of a fastening means 5, in particular as a ring around a fastening means 5, or can be arranged between fastening means 5 within the seal 4. The thicknesses of seal 4 and inlay 14 can preferably be matched to one another in such a way that a gas-tight connection and reliable electrical contacting of burner door 3 and burner body 2 can be achieved. An inlay 4 can consist of graphite, for example.

On the right side of the 5 a plan view of the seal 4 with recesses 13 for inlays 14 is shown.

6 shows a burner 1 proposed here with a collar 16 as a contact device. The wall 18 of the gas duct 10 can be conical in order to ensure reliable electrical contact between the burner door 3 and the burner body 2 .

According to an alternative or cumulative embodiment, the collar 16 can also have at least one area in which a partial area of the collar 17 has been separated, for example punched out. This part of the collar 17 can be bent outwards in such a way that it forms a spring element that is subjected to bending stress and that improves the electrical contact.

With the solution shown here, a significant improvement in the electrical connection of burners is achieved.

Reference List

1

burner

2

torch body

3

burner door

4

poetry

5

fasteners

6

flange

7

Cable

8th

fastener

9

corresponding connector

10

gas supply

11

spring element

12

opening

13

recess

14

inlay

15

shift direction

16

collar

17

Partial collar

18

conical wall

19

recording

Claims (12)

Burner (1) for a heating device, having a burner body (2) and a burner door (3) between which a seal (4) is arranged, with an electrical connection by means of a contact device between the burner body (2) and burner door (3) in the area of a Gas supply (10) from the burner door (3) to the burner body (2) and/or within the seal (4) arranged between the burner body (2) and the burner door (3). Burner (1) after claim 1 , wherein the contact device comprises a cable (7) with a connecting element (8). Burner (1) after claim 1 wherein the contact means is provided with the seal (4). Burner (1) after claim 1 , wherein the contact device comprises at least one spring element (11) which brings about an electrically conductive connection between the burner door (3) and the burner body (2) by spring force. Burner (1) after claim 4 , wherein the at least one spring element (11) is a bending stressed spring which is firmly connected to the burner door (3) or the burner body (2). Burner (1) after claim 4 , wherein the at least one spring element (11) is a portion of the burner body (2) or the burner door (3) itself. Burner (1) after claim 4 , wherein the at least one spring element (11) is a compression-loaded spring and causes an electrically conductive connection through a recess (13) in the seal (4) by a compressive force between the burner door (3) and burner body (2). Burner (1) after claim 7 , wherein the at least one spring element (11) is arranged in an opening (12) in the burner door (3) or burner body (2). Burner (1) after claim 6 , wherein the at least one spring element (11) is arranged in the region of a fastening means (5) for connecting the burner body (2) and the burner door (3). Burner (1) after claim 4 wherein the at least one spring element (11) is a collar (16) of the gas supply (10) and is shaped in such a way that a spring force of the collar (16) acting radially outward causes an electrically conductive connection. Burner (1) after claim 1 , wherein the contact device is an inlay (14) made of electrically conductive material, which is arranged in a recess (13) in the area of a fastening means (5) for connecting the burner body (2) and burner door (3) or in a recess (13) between Fastening means (5) is arranged. Use of at least one spring element (11) and/or an electrically conductive seal (4) to bring about an electrically conductive contact between a burner door (3) and a burner body (2).

Images