EP1113223B1 - Combustion apparatus - Google Patents

Abstract

The furnace has a reservoir (5) for fuel and a supply line (6) with a screw conveyor (7) to deliver the fuel. The supply line passes through a post-combustion chamber (2) to dry the fuel. The post-combustion chamber has two flame channels or spaces to carry hot combustion gases, which are alternately connected to the combustion chamber (1) by a flap (12). The supply line runs through the first (13) flame channel. Flames or hot gases are conducted to the supply line in the second flame channel.

Description

The invention relates to a firing plant for shredded, in particular chipped and / or schnitzelförmige fuels, such as sawdust, wood chips od. Like., With a storage space for the fuel and a supply line with arranged therein Feed screw for the subsequent delivery of fuel from the storage room.

Such automatically loaded combustion plants are known. Especially Small combustion plants of this type (power up to about 50 kW) are only for relatively dry fuels with a moisture content of not more than 40 up to 50% suitable. For larger combustion plants, it is already known, a Predrying to provide in the combustion chamber, the fuel through a downward leading staircase with individual steps slowly to the actual Be supplied to the burner. These ovens are good for heating moist material at full load. Driving with partial load is hardly possible, because then a sufficient drying is not achieved.

From DE 37 17 579 A1 is also a furnace for burning moist fuels, such as sawdust, wood waste, tree bark or the like, known, the one opening in a combustion chamber, acting as a drying chamber supply channel for the fuels connected to a feeder is. This drying chamber is surrounded by channels that trap the flue gases after passing through the heat exchanger.

The object of the invention is a firing system of the type mentioned to provide, which in addition to dry fuels for burning of wet fuels with a moisture content of over 50%. According to the invention, this is achieved by drying nachzulieferndem Fuel, the supply line passes through a Nachverbrennungsraum, wherein in the afterburner first and second flame channels or rooms for Passage of the hot combustion gases are provided, which via a flap are alternately connectable to the combustion chamber, wherein the supply line passes through one of these flame channels or spaces and in the other These flame channels or spaces the flame or hot combustion gases be passed past the supply line substantially. In this way can be a complete drying of the fuel before it is fed be achieved in the combustion chamber, even in small combustion plants. Likewise, dry fuels can be burned.

In a first preferred embodiment of the invention, the feed line opens in a known combustion chamber with a lower burnup. In such a combustion zone is on a lower portion of the fuels limited in the combustion chamber and the combustion gases pull laterally from the combustion chamber in a Nachverbrennungsraum from. It will this in conjunction with the predried fuels a very effective as well as a compactly designed firing system.

Conveniently, it is provided that a shut-off device between a provided at the top and a lower portion of the combustion chamber is by which the slippage of fuel from the top of the combustion chamber is interruptible. To switch off the firing system can this shut-off device are closed, being above the shut-off device already pre-dried material is located, so that a later restart the furnace is easily possible.

In another embodiment of the invention, the feed line opens in a storage room for dried fuel. From this leads another Supply line with arranged therein auger in a combustion chamber the furnace. In this embodiment, the shutdown is the firing system in a very simple manner possible by the screw conveyor the further supply line from the storage room into the combustion chamber is switched off. To restart the furnace Dried fuel is available in the storage room.

Conveniently, it is provided that the flap, over which the first and second Flame channels or spaces for the passage of hot combustion gases are alternately connectable to the combustion chamber, from a control device is actuated depending on the humidity of the fuel. It can thereby for different moisture contents of the supplied Fuels each achieve optimum drying, without the fuels already pre-burn in the supply line. The flap can from the control device also switched in relatively short time intervals to the fuel during its passage through the feed line to supply the optimal amount of heat for drying.

Preferably, it is provided that the screw conveyor areas with different Having slopes, followed by the storage room a Area is provided with a smaller slope than in the area where the Supply line through the flame channel or space for carrying out the combustion gases runs. As a result, this is the supply of the screw conveyor recorded material in the area of the supply line, in the afterburning room is spread over a greater length so that the fuels in the Area of larger slope only partially fill the auger. In the Drying forming water vapor or the resulting gases can easily peel off.

Preferably, it is further provided that in the combustion chamber at least a pipe is provided which extends from an upper region of the combustion chamber in a lower region of the combustion chamber, preferably below the grate, for the discharge of the drying of the fuel extends in the supply line formed vapor or gas. It gets it the derivation of the forming during drying water vapor or the thereby forming gases in the combustion chamber and on in the afterburner facilitates, in which burned the combustible components become.

Fig. 1

einen schematischen Schnitt einer erfindungsgemäßen Feuerungsanlage entlang der Linie A-A von Fig. 3;

Fig. 2

einen schematischen Querschnitt entlang der Linie B-B von Fig. 1 und

Fig. 3

einen schematischen Schnitt entlang der Linie C-C von Fig. 1.

Further advantages and details of the invention are explained below with reference to the embodiment of the invention shown in the drawing. In this show:

Fig. 1

a schematic section of a furnace according to the invention along the line AA of Fig. 3;

Fig. 2

a schematic cross section along the line BB of Fig. 1 and

Fig. 3

a schematic section along the line CC of Fig. 1.

In the embodiment of a device according to the invention shown schematically in the figures Furnace are the in a combustion chamber. 1 and afterburning space 2 formed hot combustion gases through a (Only schematically indicated in the figures) heat exchanger 3 out and escape through the fireplace 4. The firing system is in a pantry 5 stored fuel automatically charged. As fuels can all possible organic, comminuted fuels, such as sawdust, wood chips od. Like., Be provided.

The automatic feeding is done by a supply line 6, in which one of a motor 8 driven screw conveyor 7 is arranged. The feed line 6 opens into the Vebrennungsraum 1, in which a lower burn or under fire he follows. For this purpose, in the combustion chamber 1 is a V-shaped, open at the bottom Metal part 9 is provided, which is arranged above a grid 10 and extends over the length of the combustion chamber 1. The burning zone lies in the area of the outer surface of this V-shaped metal part 9. The case formed gases flow at the lower edges of the V-shaped metal part. 9 past or through the grid 10 and escape through the opening 11 the combustion chamber 1 and get into the afterburner 2. Heating systems with such combustion chambers or afterburning spaces are known. In a known manner, fresh air supply openings are both provided in the combustion chamber as well as in the afterburning space, which are not shown in the figures. The opening degree of these Frischluftzuführöffnungen can in a known manner by a likewise not shown Control device depending on the desired performance of the furnace be set.

In Nachverbrennungsraum 2, a flap 12 is arranged, which in a first Position a first space for carrying out the combustion gases or a flame channel 13 releases and in a second, shown in broken lines in Fig. 1 Position a second space to carry out the hot combustion gases or a flame channel 14 releases. The rooms or flame channels 13, 14 run along or in a fireclay 15, of which the remaining Part of the afterburning space 2 is filled. The first room or Flame channel 13 runs first up and then along the top of the afterburning space 2 horizontally to one to the heat exchanger. 3 leading opening 16. Through this horizontal part of the room or flame channel 13 extends the supply line 6. In the position shown in FIG Flap 12 is thus that in the supply line 6 in the region of the room or Flame channel 13 is located combustion material and thereby dried. The thereby forming water vapor or the thereby forming Gases enter the combustion chamber 1 and partly through it dried combustion material, partly through the tubes 17, 18, to the opening 11 and further into the afterburning space 2, in which the combustible components are burned.

To the outflow of water vapor formed during the drying or the To facilitate formed gases, the screw conveyor 7 has areas with different Slope on, as indicated schematically in Fig. 1. Im on the storage space 5 subsequent area of the screw, the slope is essential less than in the area of the afterburning space 2. This will the recorded from the storage space 5 of the screw conveyor 7 material in Area of Nachverbrennungsraumes 2 distributed over a greater length, so that the fuels in the region of the larger slope the auger only partially fill.

The promotion of the fuel via the screw conveyor 7 is preferably carried out intermittently: In the combustion chamber 1, a level sensor is arranged. When the level in the combustion chamber 1 falls below a certain value is, the engine 8 is turned on and just as much fuel in the combustion chamber 1 promoted, as before in the supply line 6 in the inside the post-combustion chamber has been dried. After switching off the motor 8 is thus the entire supply with moist Fuel filled.

If dry fuel is used from the outset or if the fuel located in the lying within the afterburner space 2 area is already dried, before an after-production in the combustion chamber 1 is necessary, the flap 12 is shown in the dashed lines in Fig. 1 Position pivoted. For passing through the opening 11 flame and the formed combustion gases thus becomes the second space or flame channel 14 released. This first leads horizontally through the fireclay 15, wherein it forms an angle to the longitudinal center axis 19 and thereby of the Longitudinal axis 19 leads away. In another area, it runs vertically above and opens either in a further opening in the heat exchanger. 3 or impinges on the horizontal portion of the first flame channel 13 on the one hand another, perpendicular to the longitudinal axis of the furnace extending, the horizontal portion of the second flame channel 14 is provided his or the horizontal portion of the first flame channel 13 extends over the entire width of the incinerator 2. In any case, thereby the hot combustion gases substantially past the supply line 6 led into the heat exchanger 3.

If only wet fuel is used to operate the firing system should be used after the shutdown of the furnace sufficient be stored dried fuel to a later startup and Allow drying of additional fuel. This is in the combustion chamber 1 a shut-off device 20 is provided. Prevented in the closed state this slipping of fuel from the top of the combustion chamber 1, in which the storage of dried fuel thus he follows. The below the shut-off 20 still existing fuel burns after closing the shut-off device and then extinguished the embers in the burning zone on the outsides of the V-shaped metal part 9. To reboot the shut-off device 20 is opened and the Dried fuel stored above drops onto the V-shaped metal part 9 and cover this. The ignition of the fuel takes place in a known manner by a hot air blower, which on one or both of the lower edges of the side parts directed the V-shaped metal part.

In a further embodiment of the invention, the supply line instead of in the combustion chamber also in a separate storage room for dried Lead to fuel. For this would be another supply line with it arranged screw conveyor lead into the combustion chamber. Such Firing system could also be a single instead of multiple combustion chambers Have combustion chamber to which the dried fuel is supplied. This Combustion chamber could turn several flame channels or spaces through which the hot combustion gases are guided, having a flap is provided for switching between these flame channels or rooms and by one of these flame channels or spaces the supply line for subsequent delivery the fuel runs.

With a firing system according to the invention can also wet fuels be easily burned with a moisture content of 60 to 70%. On Shutdown and a later restart is easy to implement. The inventive Furnace is suitable in a very special way for small combustion plants with a power of up to 50 kW, as for example in single-family homes be used.

Key to the REFERENCE NUMBERS

1

combustion chamber

2

afterburning

3

heat exchangers

4

fireplace

5

pantry

6

feed

7

Auger

8th

engine

9

V-shaped metal part

10

grating

11

opening

12

flap

13

first flame channel

14

second flame channel

15

firebrick

16

opening

17

pipe

18

pipe

19

Longitudinal central axis

20

shut-off

Claims (7)

1. A combustion plant for comminuted fuels, in particular in the form of shavings and/or chippings, such as sawdust, chopped-up material or the like, with a storage chamber (5) for the fuel and a supply line (6) with a conveying screw arranged in it for the subsequent delivery of fuel from the storage chamber, characterized in that, in order to dry fuel to be subsequently delivered, the supply line (6) extends through a post-combustion chamber (2), wherein first and second flame ducts (13, 14) or chambers for conveying the hot combustion gases are provided in the post-combustion chamber, the flame ducts (13, 14) or chambers being capable of being connected to the combustion chamber (1) in an alternating manner by way of a flap (12), wherein the supply line extends through one of the said flame ducts (13) or chambers and the flame or hot combustion gases are substantially conveyed past the supply line (6) in the other of the said flame ducts (14) or chambers.
2. A combustion plant according to Claim 1, characterized in that the supply line (6) opens into a combustion chamber (1) known per se which is designed for a lower burning and which is preferably connected to a post-combustion chamber (2).
3. A combustion plant according to Claim 2, characterized in that a shut-off device (20) is provided between an upper and a lower region of the combustion chamber (1), through which shut-off device (20) the descent of fuel from the upper region of the combustion chamber (1) is capable of being interrupted.
4. A combustion plant according to Claim 1, characterized in that the supply line (6) opens into a storage chamber for dried fuel, from which storage chamber a further supply line with a conveying screw arranged in it leads into a combustion chamber.
5. A combustion plant according to one of Claims 1 to 4, characterized in that the flap (12) is capable of being actuated by a control device in a manner dependent upon the moisture of the fuel.
6. A combustion plant according to one of Claims 1 to 5, characterized in that the conveying screw (7) has regions with different pitches, wherein a region is provided which has a lower pitch adjacent to the storage chamber (5) than in the region in which the supply line (6) extends through the flame duct (13) or chamber for the passage of the combustion gases.
7. A combustion plant according to one of Claims 1 to 6, characterized in that at least one pipe (17, 18) is provided in the combustion chamber (1), the said pipe (17, 18) extending from an upper region of the combustion chamber (1) into a lower region of the combustion chamber (1), preferably as far as below the grate (10), in order to remove the vapour or gas formed during the drying of the fuel in the supply line (6).

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