Burner Unit, Furnace and Method for Operation

Abstract

The invention relates to a burner unit for a furnace, in particular a continuous furnace, a tunnel furnace or the like, to a furnace and to a method for operating a furnace, the burner unit having at least two burners which are configured for burning a combustion gas, the burner unit having a gas pipe and an air pipe for supplying the burners with combustion gas, the burner unit having at least one gas metering valve in the gas pipe and at least one air metering valve in the air pipe, the gas metering valve and the air metering valve being controllable by means of a shared control device, the gas metering valve being a magnet valve and the air metering valve being a magnet valve as well.

Claims

1-16. (canceled)

17. A burner unit for a furnace, comprising: at least two burners configured for burning a combustion gas; a gas pipe; an air pipe; at least one gas metering valve in the gas pipe; at least one air metering valve in the air pipe; and a shared control device adapted for controlling the at least one gas metering valve and the at least one air metering valve wherein the at least one gas metering valve and the at least one air metering valve are magnet valves.

18. The burner unit according to claim 17, further including a regulating apparatus configured for synchronizing a corresponding operating state of the at least one gas metering valve and the at least one air metering valve.

19. The burner unit according to claim 17 wherein the gas pipe and the air pipe are branched toward the at least two burners, the at least two burners being switched in series at the gas pipe and the air pipe.

20. The burner unit according to claim 17, including one gas metering valve and one air metering valve assigned to each burner.

21. The burner unit according to claim 17, including a check valve in (a) the gas pipe, (b) the air pipe or (c) the gas pipe and the air pipe of the burner unit.

22. The burner unit according to claim 17, including a check valve in (a) the gas pipe, (b) the air pipe or (c) the gas pipe and the air pipe of each burner.

23. The burner unit according to claim 17, wherein an opening cross section of the at least one air metering valve is larger than an opening cross section of the at least one gas metering valve.

24. The burner unit of claim 17, wherein the burner unit has at least 3 or more burners.

25. The burner unit of claim 17, further including a fan adapted for conveying air into the air pipe.

26. The burner unit of claim 17, wherein the air pipe of the burner unit is connected to a central air circulation pipe of a furnace.

27. A furnace having at least one burner unit as set forth in claim 17.

28. A method for operating a furnace, comprising: supplying a combustion gas to at least two burners via a gas pipe and an air pipe; and controlling at least one gas metering valve in the gas pipe and at least one air metering valve in the air pipe by a shared control device by synchronously opening and closing the at least one gas metering valve and the at least one air metering valve with a regulating apparatus.

29. The method of claim 28, including regulating an operating state of the at least one air metering valve as a reference variable according to an operating state of the at least one gas metering valve.

30. The method of claim 28, including regulating the combustion gas in a stoichiometric relationship.

31. The method of claim 28, including regulating the at least one gas metering valve according to a requirement of (a) a burner performance, (b) a furnace temperature or (c) a burner performance and a furnace temperature as a reference variable of the shared control device.

32. The method of claim 28, including executing the opening and the closing at a stroke of at least 50 strokes/minute.

33. The method of claim 28, including executing the opening and the closing at a stroke of at least 100 strokes/minute, up to 400 strokes/minute.

34. The method of claim 28, including executing the opening and the closing at a stroke of at least 200 strokes/minute, up to 400 strokes/minute.

35. The method of claim 28, including (a) initiating, by the shared control device, a sequence of strokes of an opening and closing when a lower furnace temperature is not met, (b) terminating, by the shared control device, the sequence of strokes when an upper furnace temperature is exceeded and (c) regulating, by the shared control device, burner performance by varying stoke time, stroke duration or stroke time and stroke duration.

36. The method of claim 28, including metering air at a temperature below 70? C. via the at least one air metering valve and generating a temperature of up to 400? C. in the furnace.

Description

BRIEF DESCRIPTION OF THE DRAWING FIGURES

[0026] In the following, a preferred embodiment of the invention is described in more detail with reference to the enclosed drawings.

[0027] FIG. 1 shows an embodiment of a burner unit according to the state of the art;

[0028] FIG. 2 shows another embodiment of a burner unit;

[0029] FIG. 3 shows an embodiment of a magnet valve in a cut view;

[0030] FIG. 4 shows a diagram with operating states of magnet valves of a burner unit.

DETAILED DESCRIPTION

[0031] FIG. 1 shows a burner unit 10, as known from the state of the art. Burner unit 10 is positioned on a furnace top 11 of a tunnel 12 of a furnace 13 and shown in a top view in this instance. Burner unit 10 essentially comprises burners 14 (symbolically shown), by means of which a combustion gas is supplied to an interior of furnace 13 (not shown in this instance) and burned there. Furthermore, burner unit 10 comprises an air pipe 15 and a gas pipe (not shown in this instance), which supplies burners 14 with gas. The gas pipe has gas metering valves, which are each assigned to a burner 14 and meter a volumetric flow of gas to burners 14. The gas metering valves are formed by magnet valves.

[0032] Burner unit 10 further comprises a fan 16, which is disposed at an end 17 of air pipe 15, and suctions air from surroundings 18 of furnace 13 and conveys it to air pipe 15. Air pipe 15 branches towards corresponding burner 14 via branches 19, meaning burners 14 can be supplied with air. In corresponding branches 19 of air pipe 15, check valves 20 are disposed, which are manually actuatable and allow a complete blocking of air pipe 15 at this location. Furthermore, an air metering valve 21 is provided, which is disposed essentially at end 17 of air pipe 15 downstream of fan 16 in a flow direction of the air. Air metering valve 21 has a servomotor 22 and a flap (not shown in this instance) within air pipe 15. Via air metering valve 21, a volumetric flow of air supplied to burners 14 can be set by air supplied to burners 14. By means of a control device (not shown in this instance) of burner unit 10, air metering valve 21 is set such that a sufficient amount of air is always available for a complete combustion of the gas within furnace 13.

[0033] FIG. 2 shows a burner unit 23, in which, in contrast to the burner unit of FIG. 1, fan 16 is connected directly to air pipe 15, without an interconnected valve, at end 17 of air pipe 15. In contrast, an air metering valve 24 is provided special for each burner 14 at air pipe 15 and/or branches 19, air metering valve 24 being formed by a magnet valve 25. The air supplied in air pipe 15 via fan 16 can be conveyed to corresponding burner 14 via air metering valve 24.

[0034] FIG. 3 exemplarily shows a magnet valve 26, which can find use for burner unit 23. Depending on a structural size or a pipe cross section 27 of magnet valve 26, magnet valve 26 is usable as an air metering valve or a gas metering valve. Pipe cross section 27 is comparatively larger for an air metering valve than for a gas metering valve. Magnet valve 26 is formed having a valve casing 28 and an actuation device 29. Actuation device 29 comprises a piston 30 and an electromagnetic coil 31. Valve casing 28 forms a first chamber 32 and a second chamber 33, which serve for connecting a medium pipe (not shown). In the exemplary embodiment, a flow direction of a medium to chamber 33 indicated by arrow 34 is provided. Further, a valve seat 35 is formed in valve casing 28, which is closable with a valve sealing element 36 disposed on piston 30. Valve seal element 36 of piston 30 is pressed in such a manner against valve seat 35 by means of a spring 37 that magnet valve 26 is closed. Magnet valve 26 is opened by actuating piston 30 by means of electromagnetic coil 31 and thus by lifting valve seal element 36 from valve seat 35. A gaseous medium can then flow from first chamber 32 to second chamber 33. The actuation can take place in a sequence of strokes by opening and closing the magnet valve 26. Piston 30 has a bypass hole (not shown) of several millimeters' diameter. Flushing air flows through this bypass bore, the flushing air protecting a burner head from becoming overheated during a closed position of piston 30.

[0035] FIG. 4 shows a diagram having a first sequence 38 of strokes for opening and closing a gas metering valve, as is used for a burner unit according to FIG. 2, with reference to a temporal sequence. A line 39 represents an open position 40 and a closed position 41 of the corresponding gas metering valve. Furthermore, a sequence 42 of strokes for opening and closing an air metering valve according to the state of the art, as can be used for the burner unit according to FIG. 1, is shown. An opening and closing is only slowly possible in this instance, meaning air can still continue to flow through the air metering valve during closed position 41 of the gas metering valve, and thus excess air enters the interior of a furnace, the air having to be heated in order to maintain the desired furnace temperature. Furthermore, a sequence 43 of strokes for opening and closing an air metering valve is shown, as can be used for the burner unit according to FIG. 2. In this instance, sequence 43 of strokes is synchronized insofar with sequence 38 of strokes that an optimal amount of air for combustion is supplied to the furnace. A heating of an excess amount of air in the furnace is then no longer required, whereby a significant saving in costs is yielded.