EP2014979A2 - Operating device for a high-power surface burner and operating method for same - Google Patents

Abstract

The surface burner (3) is supplied with air through lines (8, 6) to and from the blower (5). The gas pressure regulator (9) controls the pressure in the line (7) and is operated by an actuator (10) having a control input (25) connected to a solenoid valve (26). During ignition, this sends a pressure signal to the control input, causing enrichment of the mixture supplied to the burner. The control input alters the pressure reference value controlled by the regulator (9). The regulator sets the gas pressure to a first value for operation of the burner. It sets the pressure to a second value for ignition. An independent claim IS INCLUDED FOR the corresponding method of ignition of a high power surface burner.

Description

The invention relates to a regulator device for a surface burner and to a method for igniting such a surface burner.

So-called surface burners up to a capacity of approx. 100 kW have been available for some time. The surface burners are characterized by a large, mostly cylindrical burner surface, which is provided with a plurality of fuel / air outlet openings. To the Outlets burn relatively small flames, so that the burner is covered on its surface by a layer of flame.

There are efforts to use surface burners up to the power range of, for example, one megawatt. It turns out that the ignition of such a burner can be a problem. In particular, it is difficult to achieve a safe propagation of the flames over the entire burner surface within the safety period.

An operating device, which also allows the operation of a surface burner is, for example, from DE 10 2004 038 673 B3 known. This operating device has a fan which generates a gas / air mixture for supplying the burner. The fan draws in air and gas. Gas is provided via a gas pressure regulator. This is controlled on the one hand by the gas pressure of the gas line leading to the fan and on the other hand by the ambient air pressure. In this way, the gas pressure regulator automatically adjusts the gas pressure to the variable ambient air pressure so that a desired gas / air mixture is maintained relatively independently of ambient air pressure fluctuations.

It is an object of the invention to provide an operating device for operating a surface burner, which allows simple means a safe ignition of the burner.

• Die erfindungsgemäße Betriebseinrichtung für den Oberflächenbrenner enthält eine luftführende Leitung und einen Gasdruckregler. Der Gasdruckregler ist mit einer Stelleinrichtung versehen, die an einem Steuereingang einen Referenzdruck erhält. Eine zu der Betriebseinrichtung gehörige Steuereinrichtung liefert zum Zünden des Brenners ein Drucksignal an den Steuereingang, um dadurch den Gasdruckregler zu einem höheren Gasdruck hin zu verstellen. Der Gasdruckregler liefert somit über die Gasleitung einen größeren Gasstrom an den Brenner, was zu einer Anfettung des zu dem Brenner gelieferten Gas/Luft-Gemischs führt. Die Anfettung bewirkt ein sicheres Zünden des Brenners. Wird dieser an einer Stelle, beispielsweise durch elektrischen Funkenüberschlag gezündet, pflanzen sich die Flammen ohne Schwierigkeiten über die gesamte Oberfläche des Oberflächenbrenners fort, ohne dass es dazu besonderer konstruktiver Maßnahmen an dem Oberflächenbrenner bedürfte. Durch die Anfettung des Gas/Luft-Gemischs wird eine weiche und sichere Zündung erreicht. Das Überzünden einer Flamme, die an einer der Öffnungen des Oberflächenbrenners brennt, auf benachbarte Gebiete bzw. Düsen ist leichter möglich als es im Betrieb mit demjenigen Gas/Luft-Gemisch erreicht werden, wie es zum Betrieb des Brenners vorgesehen ist. Die Anfettung des Gas/Luft-Gemischs gestattet insbesondere die Reduktion der Brennerleistung während des Zündbetriebs, d.h. die Reduktion des dem Brenner zugeführten Massenstroms, so dass eine besondere leise und unspektakuläre Zündung des Brenners erreicht wird.

This object is achieved with the operating device according to claim 1 as well as with the method according to claim 10:

• The operating device according to the invention for the surface burner contains an air-carrying pipe and a gas pressure regulator. The gas pressure regulator is provided with an adjusting device which receives a reference pressure at a control input. A control device associated with the operating device supplies a pressure signal to the control input for igniting the burner, thereby adjusting the gas pressure regulator to a higher gas pressure. The gas pressure regulator thus supplies via the gas line a larger gas flow to the burner, which leads to an enrichment of the gas / air mixture supplied to the burner. The enrichment causes a safe ignition of the burner. If this is ignited at one point, for example by electric flashover, the flames propagate without difficulty over the entire surface of the surface burner, without the need for special constructive measures on the surface burner. By enriching the gas / air mixture a soft and safe ignition is achieved. The overflamming of a flame burning at one of the openings of the surface burner to adjacent areas or nozzles is easier to achieve than when operating with the gas / air mixture as provided for operation of the burner. The enrichment of the gas / air mixture allows in particular the reduction of the burner power during the ignition operation, ie the reduction of the burner supplied mass flow, so that a special quiet and unspectacular ignition of the burner is achieved.

The increase in the pressure supplied by the gas pressure regulator or the enrichment of the gas / air mixture preferably takes place within a period of time in which sparkover arcs are generated at the surface burner via a high-voltage ignition device.

Preferably, the adjustment of the gas pressure regulator achieved by the provided for influencing a predetermined reference value control input, which is in normal burner operation in communication with the ambient air pressure, is subjected to an increased pressure. The gas pressure regulator thus supplies during the ignition operation a gas pressure which would correspond to a higher air pressure. However, because the higher air pressure is actually absent, this results in enrichment of the gas / air mixture.

The influencing of the reference value for the gas pressure is preferably effected by switching between two pressure stages, namely a) ambient pressure and b) increased other pressure. The switching can be done by a valve assembly with a directional control valve or other valves. These are preferably electrically controlled and receive a pulse from a control device, for example a so-called automatic burner control or even a circuit branch of the high-voltage ignition device of the burner.

The increased pressure level can be tapped, for example, at the leading to the burner fan output. It is alternatively possible to use other sources of pressure.

The adjusting device preferably includes a fluid actuator for actuating the gas pressure regulator. The fluid actuator is associated with a control arrangement, for example in the form of a pressure cell, the membrane is acted upon on one side of the reference pressure. The diaphragm of the pressure cell preferably controls a drain valve to regulate the actuating pressure of the actuator.

Preferably, the burner is preceded by a fan. The fan has a connected to the burner Pressure side and a suction side, where the gas coming from the gas pressure regulator can be supplied. At different blower speeds, a correspondingly different negative pressure is created at the blower inlet. This negative pressure continues across the mouth of the gas line up to the gas pressure regulator, which wants to compensate for the negative pressure by appropriate gas supply. Accordingly, the delivered amount of gas automatically adapts to the amount of air delivered by the fan. This is especially true when the gas is passed through a jet pump assembly in the fan, which is connected to the diffuser of the jet pump, while the gas line with the drive nozzle of the jet pump and the suction port are connected to the ambient air. Control of the fan speed and lowering of the same to ignite the burner causes the ignition of the burner with reduced power.

• Figur 1 einen Oberflächenbrenner mit zugeordneter Betriebseinrichtung in schematisierter Darstellung,
• Figur 2 einen zu der Betriebseinrichtung gehörigen Gasdruckregler in schematisierter Darstellung,
• Figur 3 das Gebläse und eine Ventilanordnung für die Betriebseinrichtung nach Figur 1 in einer alternativen Ausführungsform und in schematisierter Darstellung und
• Figur 4 das Gebläse und die Betriebseinrichtung für den Brenner in einer ausschnittsweisen schematisierten Darstellung.

Further details of advantageous embodiments of the invention are the subject of the drawing, the description and claims. The description is limited to essential aspects of the invention and other circumstances. The drawing discloses further details and is additionally to be used. Show it:

• FIG. 1 a surface burner with associated operating device in a schematic representation,
• FIG. 2 a gas pressure regulator belonging to the operating device in a schematic representation,
• FIG. 3 the fan and a valve assembly for the operating device after FIG. 1 in an alternative embodiment and in schematic representation and
• FIG. 4 the blower and the operating equipment for the burner in a fragmentary schematic representation.

In FIG. 1 an operating device 1 for a surface burner 2 is illustrated. The surface burner 2 has, for example, a cylindrical lateral surface 3 with a multiplicity of nozzle openings 4, from which a gas / air mixture emerges during operation and forms flames. This surface burner 2 may have a power of up to 1 MW or more. Its active surface provided with nozzle openings 4 may comprise one or more square meters.

The operating device 1 has a blower 5 which supplies the surface burner 2 with a gas / air mixture. The output of the blower 5 is connected via a line 6 to the surface burner 2. The fan 5 is supplied via a gas line 7 gas and air via corresponding Luftansaugöffnungen or a line 8. Here the fan sucks 5 ambient air. The gas line 7 receives gas via a gas pressure regulator 9 with an adjusting device 10. It is adapted to generate in the line 7 a gas pressure which is in a fixed relationship to the ambient air pressure. For example, the gas pressure in the gas duct 7 will be adjusted to the ambient air pressure, i. adjusted to zero millibars. At the Gebläseeingang also a gas / air mixing means may be provided to supply the fan with a gas / air mixture.

The adjusting device 10 is actuated to regulate the gas pressure in the gas line 7, a valve 11 which in FIG. 2 is illustrated in its schematic structure. It has a valve closure member in the form of a regulator plate 12, which more or less throttles the gas flow in the gas line 7 depending on its setting position. The regulator plate 12 is connected via a connecting member, for example a push rod 13, with a diaphragm 14 of a fluid actuator 15. In this, the membrane 14 shares a Working chamber 16 from. While a compression spring 17 or other spring means preloaded the regulator plate 12 in its closed position, a positive pressure in the working chamber 16 leads to the opening of the valve 11. The working chamber 16 is connected via a throttle 17 with the front of the valve 11 lying part of the gas line. 7 connected. In addition, leads from the working chamber 16 a line to a control valve 18 of a pressure cell 19, which contains a control diaphragm 20. The control diaphragm 20 divides the interior of the pressure cell 19 into an outer chamber 21 and an inner chamber 22. The inner chamber 22 is connected via a line 23 to the part of the gas line 7 located downstream of the valve 11. It also contains the control valve 18, the mouth of which can be closed by the membrane 20 or a closing member actuated by the membrane 20.

A spring 24, which may be disposed in the outer chamber 21, biases the diaphragm 20 against the control valve 18.

The outer chamber 21 is connected via a line 25 to a control member 26, for example in the form of a valve assembly 27. The line 25 forms a control input for acting on the adjusting device with a pressure signal, in this case a reference pressure signal. The valve assembly 27 is formed in the present embodiment by a 3/2-way valve 28 (2 positions, 3 connections). This 3/2-way valve may be connected to an electrical, electromagnetic or other actuating mechanism. This is controlled via an electrical line by a control unit 29, for example in the form of an automatic burner or by another electrical circuit, such as a Hochspannungszündschaltung 30, which in turn may be controlled by the control unit 29. The Hochspannungszündschaltung 30 is used for Generating electrical flashovers between a firing electrode 31 and the surface burner 3 for firing it at a selected location.

The control unit 29 is connected via a line 32 to a signal generator, which supplies, for example, a heat request signal. The control unit 29 may further with the blower, in particular with a FIG. 4 be visible blower motor M connected to the blower power or speed or the mass flow promoted by the blower targeted to influence.

The 3/2-way valve 28 serves to connect the line 25 alternatively via a port 33 ambient air pressure, i. a first pressure level and via a line 34 with a second pressure level, for example, to connect the blower outlet pressure on the line 6.

To further illustrate the operating device 1 is on FIG. 4 referenced, in particular the fan 5 illustrates. It has the motor M, on the shaft of a fan 35 sits. At the periphery of the blower housing 36, the line 6 connects, via which a gas / air mixture is fed to the burner 3. Centrally approximately centrally of the blower housing 36, a jet pump or Venturianordnung 37 is provided. Radially to this air is sucked by the fan 5. The venturi arrangement 37 has a diffuser 38. In front of the diffuser 38 is an air-suction channel 39. At the air-suction channel 39, a gas nozzle 40 is provided, is provided at the valve 11 via the gas at a given pressure. Immediately before the nozzle 40, the line 23 takes the gas pressure.

• Es wird zunächst davon ausgegangen, dass der Brenner 3 nicht in Betrieb ist. Erhält die Steuereinheit 29 nun über die Leitung 32 ein Wärmeanforderungssignal, setzt sie das Gebläse 5 in Gang. Die Steuereinheit 29 wählt dabei vorzugsweise eine Gebläsedrehzahl, die nicht der vollen Leistung des Brenners 3 sondern einer reduzierten Leistung - der Zündleistung - entspricht. Diese beträgt beispielsweise 20 bis 30 % der Nennleistung des Brenners 3.

The operating device 1 described so far operates as follows:

• It is initially assumed that the burner 3 is not in operation. If the control unit 29 now receives a heat request signal via the line 32, it sets the fan 5 in motion. The control unit 29 preferably selects a fan speed, which does not correspond to the full power of the burner 3 but a reduced power - the ignition performance. This is, for example 20 to 30% of the rated power of the burner. 3

At the same time, the control unit 29 activates the Hochspannungszündschaltung 30 to generate spark flashes on the ignition electrode 31. Furthermore, the control unit 29 switches the 3/2-way valve 28 in the in FIG. 1 illustrated position in which the control input 25 of the actuator 10 is connected to the fan output on line 6. As a result, the outer chamber 21 of the pressure box 19 receives a reference pressure which is above the atmospheric air pressure. Accordingly, the control valve 18 closes something, whereby the pressure in the working chamber 16 is increased and the valve 11 is opened further. An increased gas pressure is now applied to the nozzle 40, which leads to an increased gas supply and thus to an enrichment of the gas / air mixture. The burner 3 ignites soft and, above all, quite quickly over the entire surface.

As soon as an ignition time has expired or the ignition of the burner 3 has been detected with corresponding detector means, the control unit 29 changes over from ignition operation to regular operation. For this purpose, it deactivates the Hochspannungszündschaltung 30 and switches the 3/2-way valve 28 so that the line 25 and the control input of the actuator 10 is connected to the terminal 33. In other words, the outer chamber 21 is connected to the ambient air pressure. The pressure relief of the outer chamber 21 causes now an adjustment of the gas pressure regulator 9 to a lower gas pressure, whereby the amount of gas supplied via the nozzle 40 is reduced. The result is a leaner mixture and the burner 3 goes into its normal operation.

In normal operation, the power of the burner 3 may be e.g. be controlled by the fan speed. As the fan speed increases, so too does the suction on the venturi assembly 37 and on the nozzle 40. Because the gas pressure regulator 9 keeps the gas pressure constant, the amount of gas discharged through the nozzle 40 increases. The performance of the burner 3 can thereby be changed in a wide range in the ideal case, in the ratio of up to 1:10.

FIG. 3 illustrates a modified embodiment of the valve assembly 27. Instead of the 3/2-way valve 28, two individual open / close valves 28a, 28b are provided. Valve 28a connects line 25 to ambient air pressure port 33 while valve 28b connects line 25 to line 34. The valves 28a, 28b are opened or closed alternately. When ignited, the valve 28b is open. In normal operation, the valve 28a is open.

The control input of the adjusting device 10 may be formed instead of the line 25 in other ways. For example, the control input can be formed by the electrical actuating connection of the valve arrangement 27, which thus becomes part of the adjusting device 10. The control input can also be the electrical connection of an electrically operated or controlled valve, which releases a bypass channel to the throttle 17 or adjusts the throttle 17 to change the pressure of the gas pressure regulator.

For sure ignition of a surface burner 3 is an operating device 1 is provided, which is adapted to greasing the supplied gas / air mixture when igniting the burner 3. The enrichment is achieved by switching a reference pressure supplied to the actuator 10. This is preferably the ambient air pressure during normal operation while it is preferably an increased air pressure in the ignition mode, which pre-mirrors the actuator higher air density than actually present. This is a simple way of Gemischanfettung to ignite the burner.

reference numeral

1

Factory equipment

2

surface burner

3

lateral surface

4

orifices

5

fan

6

management

7

gas pipe

8th

management

9

Gas pressure regulator

10

setting device

11

Valve

12

Valve closure member / regulator plate

13

pushrod

14

membrane

15

Fluid actuator

16

working chamber

17

throttle

18

control valve

19

Vacuum unit

20

membrane

21

outer chamber

22

inner chamber

23

management

24

feather

25

management

26

control element

27

valve assembly

28

3/2-way valve

29

control unit

30

Hochspannungszündschaltung

31

ignition electrode

32

management

M

engine

33

connection

34

management

35

fan

36

fan housing

37

venturi

38

diffuser

39

Air suction channel

40

jet

Claims (15)

Operating device (1) for a surface burner (3), in particular a surface-mounted blower burner,
with a line (8, 6) leading to the burner (3),
with a gas pressure regulator (9) which regulates the gas pressure in a gas line (7) supplying the surface burner (3) and is actuated by means of an adjusting device (10) having a control input (25),
with a control member (26) connected to the control input (25) for supplying a pressure signal to the control input (25) during ignition to thereby greas the gas / air mixture of the burner (3). Operating device according to claim 1, characterized in that the control input (25) serves for influencing a predetermined reference value for the gas pressure regulated by the gas pressure regulator (9). Operating device according to claim 1, characterized in that the gas pressure regulator adjusts the gas pressure to a first pressure value for the operation of the burner (3) and a second pressure value for the ignition of the burner (3). Operating device according to claim 1, characterized in that the adjusting device (10) has a fluid actuator (15). Operating device according to claim 4, characterized in that the fluid actuator (15) is controlled by a pressure difference resulting from the gas pressure behind the gas pressure regulator (9) and a reference pressure results. Operating device according to claim 5, characterized in that the reference pressure in burner operation of the ambient pressure and in the ignition operation is a pressure to be picked up before the burner (3). Operating device according to claim 1, characterized in that the control member (26) is an electrically operated valve arrangement (27). Operating device according to claim 7, characterized in that the valve arrangement (27) is a directional control valve (28). Operating device according to claim 7, characterized in that the valve arrangement (27) comprises two on / off valves (28a, 28b). Operating device according to Claim 1, characterized in that a fan (5) is arranged in the line (6) leading to the burner (3). Operating device according to claim 8, characterized in that the gas line (7) leads to the fan (5). Operating device according to claim 9, characterized in that the gas line (7) via a jet pump assembly (37) to the fan (5) is connected. Method for igniting a surface burner, in particular a high-power surface burner (3), in which the gas pressure is increased to ignite the burner (3). A method according to claim 13, characterized in that by raising the gas pressure enrichment of the resulting gas / air mixture is brought about. A method according to claim 13, characterized in that for igniting the gas / air mixture flow is reduced.

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