EP4215816A1 - Assembly of a burner and a uv-sensor for flame monitoring of a heating device, combustion chamber for a heating device and heating device - Google Patents

Abstract

An arrangement (12) of a burner (3) and a UV sensor (13) for monitoring a flame (11) of the burner (3) is proposed, the UV sensor (13) having a detection line (15), in which a flame (11) can be detected, and a distance (20) between the surface (21) of the burner (3) and the detection line (15) varies. According to a preferred embodiment of the invention, the arrangement (12) of burner (3) and UV sensor (13) can be designed in such a way that the detection line (15) of the UV sensor (13) largely covers the entire flame field (17), in particular from the lower limit (18) to the upper limit (19) penetrates. Reliable flame monitoring over the entire modulation range of the heater (1) can thus be advantageously ensured.

Description

The invention relates to an arrangement of a burner and a UV sensor for flame monitoring of a heating device, a combustion chamber for a heating device and a heating device.

Heating devices that provide heat by burning a fuel usually have a burner that can burn a mixture of the fuel and ambient air. In order to prevent unburned fuel or a mixture of fuel and combustion air from escaping, flame monitoring devices are often provided or even required by law. To monitor burners that use a gaseous fuel such as natural gas or hydrogen, flame monitoring devices are usually used, which detect an ionization current based on the charge carriers released during combustion, and UV (ultraviolet) sensors, which can detect the UV radiation emitted by the flame and thus the flame itself. UV-based systems for flame detection are often used when hydrogen is used as a fuel or fuel mixtures containing hydrogen, because hydrogen does not release sufficient charge carriers during combustion for reliable detection by means of an ionization current.

However, flame monitoring systems using a UV sensor are expensive and sensitive to heat. In addition, these have a strongly focused, largely linear, detection area. Due to this highly focused detection area, a heater can be used in different modulation (power) ranges of its size (Height) varying flames are often difficult to detect by the sensor and reliable flame monitoring is not possible in the modulation limit ranges.

Proceeding from this, it is the object of the invention to propose an arrangement of a burner and a UV sensor for flame monitoring of a heating device which at least partially overcomes the problems of the prior art described. In particular, reliable flame monitoring should be made possible in the entire modulation range (power range) of the heater.

In addition, the invention should at least not significantly increase the complexity of a heating device and only require minor structural changes to a heating device.

These objects are solved by the features of the independent patent claims. Further advantageous refinements of the solution proposed here are specified in the dependent patent claims. It is pointed out that the features listed in the patent claims can be combined with one another in any technologically sensible 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.

Contributing to this is an arrangement comprising at least one burner with a surface and a UV sensor for flame monitoring of a heater, the UV sensor having a detection line in which a flame can be detected, and a distance between the surface of the burner and the detection line varying.

The arrangement of burner and UV sensor can be used in particular in a combustion chamber of a heating device. By a - in the direction of the detection line - The varying (especially increasing and/or decreasing) distance between the burner surface and the detection line makes it possible to monitor a flame (located above the surface of the burner) in the entire modulation range, i.e. in the entire power range of the burner or heater. A course of the detection line above a small flame of the burner at low heater output (and thus the (small) flame between the burner surface and the detection line occurs), which means that the (small) flame cannot be detected by the UV sensor, can be avoided. Even a large flame of a burner operated at high power, which may appear above a detection line of a UV sensor in relation to the burner surface and could therefore also not be detected using the prior art, can be detected by the proposed arrangement with a variable distance between the burner surface and the detection line.

The heater is in particular a gas heater which is set up to burn a gaseous fuel such as natural gas or in particular hydrogen with the supply of ambient air in order to provide heat, for example for a heating circuit or a hot water supply. The heater can generally have at least one burner and a delivery device that delivers a mixture of fuel (gas) and combustion air through a mixture channel of the heater to the burner. The combustion products can then be routed through an exhaust duct of the heater to an exhaust system.

In order to prevent unburned mixture from escaping from the burner or the heating device, the heating device can have a flame monitor which, in the event of a flame loss, initiates a new ignition process or closes a gas supply to the heating device. For example, ionization electrodes can be used for flame monitoring, which detect an ionization current of the flame. When burning hydrogen as However, only a few charge carriers are released from the fuel, so that flame monitoring based on ionization currents does not appear to be possible with certainty. For flame monitoring of a hydrogen flame, the ultraviolet (UV) light emitted by the flame can be detected. One or more UV sensors can be present for this purpose. Known UV sensors can fail when exposed to high temperatures and are therefore usually arranged outside the combustion chamber.

Furthermore, known UV sensors have a limited detection range; the UV radiation can often only be detected in a linear or radial area, referred to here as the detection line.

As a rule, a combustion chamber for a heating device can have a burner door in which a burner and corresponding sensors, such as a UV sensor for flame monitoring, are arranged. The assembly and in particular the arrangement of supply lines to the combustion chamber can thus be simplified in an advantageous manner.

The burner is often, at least in part, a hollow body into which a mixture of fuel and combustion air can be introduced, which can exit the hollow body through a burner surface and burn. For this purpose, the burner surface can in particular have a large number of openings. Burners for heating devices can often have a cylindrical shape, in which case a base of the cylindrical shape can be anchored in a burner door, via which a mixture of fuel and combustion air can be supplied to the burner.

A heater can usually be operated in a power range (modulation range), with operation at low power (minimum power) a small flame occurs whose smallest distance from the burner surface is a lower limit Flame field can define. Operating with the greatest possible power (of the modulation range) results in a large flame, the greatest distance from the burner surface of which can define an upper limit of the flame field.

According to a preferred embodiment, the burner and UV sensor can be arranged in such a way that the detection line of the UV sensor largely penetrates the entire flame field, in particular from the lower limit to the upper limit. Reliable flame monitoring over the entire modulation range of the heater can thus be advantageously ensured.

According to an advantageous embodiment, the detection line of the UV sensor and the surface of the burner can be arranged at an angle to one another. In this case, the inclination can be achieved in particular by aligning the detection line or by inclining the burner surface. The inclination allows the detection line to penetrate the entire flame field, for example from the lower limit to the upper limit or vice versa. It is possible for a constant variation of the distance between the detection line and the surface of the burner to be adjustable or set up in this way

According to an advantageous embodiment, the burner can have a conical burner surface. For this purpose, the burner can be designed in particular as a (circular) truncated cone. The larger base of the truncated cone can face the burner door or face away.

According to a further aspect of the invention, a combustion chamber for a heating device is proposed, having a proposed arrangement of burner and UV sensor.

According to a further aspect, a heating device is proposed, having a combustion chamber proposed here or an arrangement of burner and UV sensor proposed here.

The details, features and advantageous configurations discussed in connection with the arrangement can accordingly also occur in the combustion chamber and the heating device presented here and vice versa. In this respect, full reference is made to the statements there for a more detailed characterization of the features.

An arrangement of a burner and a UV sensor, a combustion chamber and a heating device is thus specified here, which at least partially solves the problems described with reference to the prior art. In particular, the arrangement of a burner and a UV sensor, the combustion chamber and the heater at least contribute to enabling reliable flame monitoring of a burner of a heater for the entire modulation range with just one UV sensor.

In addition, the invention can be implemented in a particularly simple manner, since no additional built-in components or components are required compared to a heating device or burner according to the prior art.

Fig. 1:

ein hier vorgeschlagenes Heizgerät, und

Fig. 2 und Fig. 3:

eine hier vorgeschlagene Anordnung von einem Brenner und einem UV-Sensor.

The invention and the technical environment are explained in more detail below with reference to the accompanying figures. It should be pointed out that the invention should not be restricted 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:

Figure 1:

a heater proposed here, and

Figures 2 and 3:

an arrangement of a burner and a UV sensor proposed here.

1 shows an example and diagrammatically of a heater 1 proposed here. This can suck in combustion air via a combustion air supply 4 through a conveyor 2 and add a gas, for example hydrogen, to the intake volume flow of combustion air via a gas valve 5 . The combustion mixture of gas and combustion air can now be fed via a mixture channel 16 to a burner 3 which is arranged in a combustion chamber 8 and has a surface 21 . The combustion products can be fed from the combustion chamber 8 to an exhaust system 10 via an exhaust pipe 9 . The burner 3 is attached to a burner door 6, in which a UV sensor 13 can also be arranged. Protected from the high temperatures in the combustion chamber 8, the UV sensor 13 can be arranged outside the combustion chamber 8. The heater can also have a regulation and control device 7 .

2 shows an arrangement 12 proposed here of burner 3 with surface 21 and UV sensor 13 in a burner door 6. The UV sensor 13 can be arranged outside the burner door 6 and can detect UV radiation emitted by a flame of the burner 3 via a sight glass 14 on a detection line 15. In the 2 the burner 3 or the heater 1 is operated at low power, whereby a small flame 11 is formed, which can have a small distance 20 to the surface 21 of the burner 3 and can mark in a flame field 17 in the area of a lower limit 18 of the flame field 17. Due to the frustoconical design of the burner 3 and an associated variation of the distance 20 between the surface 21 of the burner 3 and the Detection line 15, the UV sensor 13 can use its detection line 15 in 2 easily detect the small flame 11 shown and ensure reliable flame monitoring.

3 shows the arrangement 12 of burner 3 with surface 21 and UV sensor 13 according to FIG 2 , but the burner 3 or the heating device 1 is operated at high power in this representation, as a result of which a large flame 11 can occur. The area with the greatest distance 20 to the surface 21 of the burner 3 of the large flame 11 can indicate an upper limit 19 of the flame field 17 . Here, too, the frustoconical design of the burner 3 and an associated variation in the distance 20 between the surface 21 of the burner 3 and the detection line 15 of the UV sensor 13 through the detection line 15 in 3 shown large flame 11 can be detected without any problems and a safe flame monitoring can be guaranteed.

Reference List

1

heater

2

conveyor

3

burner

4

supply of combustion air

5

gas valve

6

burner door

7

regulation and control unit

8th

combustion chamber

9

exhaust pipe

10

exhaust system

11

flame

12

arrangement

13

UV sensor

14

sight glass

15

detection line

16

mixture channel

17

flame field

18

lower limit

19

upper limit

20

Distance

21

surface

Claims (7)

Arrangement (12), comprising at least one burner (3) with a surface (21) having a plurality of openings through which a mixture of fuel and combustion air can exit, and a UV sensor (13) for monitoring a flame (11) of the burner (3), the UV sensor (13) having a detection line (15) in which a flame (11) can be detected, and a distance (20) between the surface (21) of the burner (3) and the detection line (15) varies. Arrangement (12) according to Claim 1, in which the detection line (15) of the UV sensor (13) and the surface (21) of the burner (3) are arranged inclined towards one another. Arrangement (12) according to any one of the preceding claims, in which the burner (3) has a conical external shape. Arrangement (12) according to one of the preceding claims, in which the burner (3) and UV sensor (13) are arranged in a burner door (6). An arrangement (12) as claimed in any one of the preceding claims, wherein the burner (3) is in the form of a truncated cone. Combustion chamber (8) for a heater (1), having an arrangement (12) according to one of the preceding claims. A heater (1) having a combustion chamber (8) according to claim 6.

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