WO2009021255A2

WO2009021255A2 - Apparatus for the combustion of solid fuel elements

Info

Publication number: WO2009021255A2
Application number: PCT/AT2008/000283
Authority: WO
Inventors: Peter Winkler
Original assignee: Peter Winkler
Priority date: 2007-08-14
Filing date: 2008-08-11
Publication date: 2009-02-19
Also published as: WO2009021255A3; AT505521A1; AT505521B1

Abstract

In an apparatus for the combustion of solid fuel elements (5), in particular of elongate fuel compacts having a round or polygonal cross section with at least five edges, comprising a combustion chamber (2) and a storage space (3) for storing a plurality of fuel elements (5), a fuel supply is provided for automatically supplying in each case one fuel element (5) from the storage space (3) into the combustion chamber (2).

Description

Apparatus for burning solid fuel elements

The invention relates to a device for burning solid fuel elements, in particular of elongated fuel compacts having a round or polygonal cross section with at least five corners, comprising a combustion chamber and a storage space for holding a plurality of fuel elements.

Solid fuel elements have become known in particular in the form of fuel pellets. As fuel often finds wood use in this context. Wood briquettes, for example, are pressed from dry, untreated wood residues, such as wood shavings, under high pressure and without the addition of binders into uniformly large and hard briquettes. Due to this high compaction during briquetting, the natural product wood assumes roughly the burning behavior of lignite, but with the difference that the wood briquettes have a lower ash and sulfur content compared to fossil fuels. Furthermore, wood briquettes are characterized by a low water content of about 10%, resulting in a relatively high energy content of 4.8 kWh per kg.

Fuel pellets have also become known in the form of so-called wood pellets. These are wood fuel pressed into small rod-shaped pellets. Such wood pellets are fired in special pellet heaters. Wood Pellet Heaters work with different feeding techniques: currently the underfeed firing, the cross insert firing, the use of a roller grate system or the downpipe or pellet firing specially developed for pellet burning. In the underfeed firing, the pellets are pressed by means of a screw conveyor from below into a burning plate, burn there and the remaining ash falls over the edge of the plate in the underlying ash container. The transverse plug-in firing function similar to the underfeed firing, except that the fuel is pushed by a screw conveyor from the side to the burner plate. In the case of the roller grate system, on the other hand, the pellets fall from above onto several slowly rotating steel discs with a small clearance. A scraper comb cleans the interspaces per revolution, so that the ashes can also fall through unhindered downwards and combustion air can be fed upwards. When the chute firing, the pellets slip over a gully in a burner pot. Through the burner pot combustion area is fixed.

The stock of wood pellets is in large burners in silos, in small burners in bags. When delivering the wood pellets in smaller bags, the pellet stove can be filled manually and the tank and conveyor systems are unnecessary. Another possibility is the delivery of pre-filled BigBags (large sacks with 1 to 2 m3 volume for up to two tons of weight). However, these require suspension systems and lifting technology.

As already mentioned, as an alternative to wood pellets, larger solid fuels in the form of briquettes have become known, with whose burning the present invention is concerned. The present invention is particularly concerned with the combustion of elongated fuel pellets of round or polygonal cross-section having at least five corners. Such mostly cylindrical fuel compacts, for example, have a diameter of about 80-90 mm and a length of about 300 mm, the combustion device are usually supplied individually, with a further pressing is supplied only after burning of the previously supplied compact. Unlike pellet heaters, the supply of fuel pellets in this case, thus significantly more complex and it would also be advantageous here to replace the manual feeders by appropriately automated feeders. The present invention therefore aims to improve a device of the type mentioned for the combustion of solid fuel elements, in particular of elongated fuel press rings with round or polygonal cross-section to the effect that the feed with the fuel pellets is simplified.

To solve this problem, the device of the type mentioned is characterized essentially by the fact that a fuel supply is provided for automatically supplying a respective fuel element from the storage space into the combustion chamber. The fact that an automatic fuel feeder is installed in the furnace, the manual refueling of another fuel element is unnecessary as soon as a fuel element is burned. Rather, a fuel element is automatically transported from the storage space into the combustion chamber by the inventive design, so that the handling is much easier. It is essential in the context of the invention here that in a controlled manner only a single fuel element is automatically transported from the storage room into the combustion chamber.

In this context, the training is preferably developed such that the fuel supply comprises a lock for detecting and transporting a single fuel element while retaining further fuel elements. Such a lock ensures on the one hand an effective sealing of the combustion chamber with respect to the storage space and on the other hand a reliable supply of a single fuel element, while preventing that further fuel elements that are held in stock in the storage room, inadvertently reach the combustion chamber.

According to a preferred development, the lock can in this case be formed by a rotatably drivable drum whose shell has a recess for detecting a fuel element during rotation. The in the coat of Drum formed recess may be adapted to the cross section of the supplied fuel elements, so that in fact only a single fuel element is certainly supplied.

Alternatively, the design can also be made such that the lock is formed by a rotatable drivable roller with a substantially circular sector-shaped cross section, wherein the circular sector has a central angle of 240-300 °, in particular 270 °. Also in this design results in a secure retention of the fuel elements not to be supplied, wherein each one supplied fuel element in the course of the rotation of the roller in the free, not filled by the circular sector cross section of the roller passes and is then taken by the roller. Preferably, the roller is formed of a plurality of substantially kreissektorförmi- gene parallel slats that pass through corresponding slots of a downwardly sloping bottom of the feeder.

In order to facilitate the supply of a fuel element from the storage space into the combustion chamber, it is provided according to a preferred development that the fuel feed has a ramp inclined downwards in the direction of the Bennraum, which forms the bottom of the storage space. On such a downwardly inclined ramp, the fuel element to be supplied in each case can roll downwards from the storage space into the combustion chamber under the influence of gravity, in which elongated fuel compacts with a round or polygonal cross section are used in the context of the present invention, so that the fuel compacts can rotate according to their longitudinal axis accordingly, while they are fed in each case by the feeder and in particular the lock in a controlled manner the fuel chamber. In order to achieve a better seal between the combustion chamber and the storage chamber, a pivotable inlet flap is preferably arranged between the reservoir and the combustion chamber, which preferably carries an actuating arm for pivoting the inlet flap. With the aid of the actuating arm, the inlet flap can be opened and closed in a controlled manner, wherein the inlet flap is preferably opened shortly before the fuel element from the reservoir into the combustion chamber and shortly thereafter closed again to minimize the amount of additionally introduced combustion air or to avoid uncontrolled air circulation

Advantageously, an ignition device is provided in the combustion chamber, which is preferably arranged on a pivotable lever. With such a design, the ignition device can be brought to the fuel element located on a grate in the combustion chamber, if necessary, wherein after switching on the ignition device, the fuel element is ignited. Thereafter, the ignition device is preferably pivoted away from the fuel element again in order to avoid destruction of the ignition device due to the high temperatures prevailing in the region of the burning fuel element.

For the controlled supply of combustion air into the combustion chamber, a combustion air channel opening into the combustion chamber is preferably provided with a combustion air flap defining the flow cross section. In this case, the combustion air flap can be pivotally mounted and carry an actuating arm for pivoting the combustion air flap, so that the flow cross-section of the combustion air duct can be adjusted in a simple manner by operating the lever.

So now not only the supply of the fuel elements but also the control of the amount of combustion air and the operation of the ignition device automated from According to a preferred development, a control device for controlling the movement of the inlet flap and / or the combustion air flap and / or the ignition device is provided. In this case, the control device can have a rotatably drivable control member, in particular control disk, with control stops which can be brought into operative connection during rotation with the actuating arm for the inlet flap and / or the pivoting lever of the ignition device and / or the actuating arm of the combustion air flap. With such a design takes place during the rotation according to the arrangement of the control stops on the control member, in particular control disc, an automatic actuation of the individual flaps or the ignition device, so that no further action is required by the user.

Preferably, the control member with the supply device, in particular drum or roller, coupled, in particular fixed to this and be rotatable together with this. In this case, as a result of the rotation of the feeding device automatically in a defined sequence actuation of the inlet flap, the ignition device or the combustion air damper, so that the supply movement is directly coupled to the control of the inlet flap, the ignition device or the combustion air damper. By suitable arrangement of the individual control stops or control cam, the time of actuation of the individual flaps or the ignition device can be defined in a defined order in a simple manner and be tuned to the controlled by the rotation of the drum or roller feeding the fuel element.

Preferably, the control disk carries two control stops, wherein the one control stop with the actuating arm for the inlet flap and the other control stop with the pivot lever of the ignition device and the actuating arm of the combustion air flap is operatively connected, so that with a number of only two control cams or control cam All functions of the device according to the invention can be set in motion. Preferably, the control stops are designed as a cam (s).

Preferably, the control disk carries markings that can be detected by sensors. Through the sensors, the current rotational position of the control disk and thus the drum can be determined, so that a function check or avoid malfunction is achievable. In this connection, according to a preferred embodiment, the markings can be formed by projections which can be detected by inductive sensors. Such a design is to be described as particularly fail-safe and reliable.

In order to trigger the delivery process in a fully automatic manner, a control circuit is advantageously provided, which is connected to the drive of the feeder. In this case, the control circuit is able to initiate the supply of a fuel element in response to various parameters, if different conditions are met. According to a preferred embodiment, the control circuit may in this case be connected, for example, to the sensors described above, so that the supply device can be driven as a function of the sensor signals. In this case, the control can be designed, for example, such that the feed device is only driven when the sensors detect a predetermined starting position of the feed device. If the predetermined starting position is not given, the control circuit, the feeder is first placed in the start position or should this not be possible, issued an error message. During operation of the feeder, ie during rotation of the drum, the sensors check the proper function and stop the operation or give an error message when unforeseen events occur. Preferably, a combustion chamber temperature sensor is additionally provided, which is connected to the control circuit. About this combustion chamber temperature sensor, the end of the combustion of a fuel element can be detected and the combustion air damper are closed, after which the spent fuel element can continue to glow for some time.

Furthermore, according to a preferred embodiment, a room temperature sensor may be provided which is connected to the control circuit. The room temperature sensor measures the current temperature in the room to be heated, wherein after falling below a set target room temperature another firing pass is started, i. E. a further fuel element is supplied into the combustion chamber as soon as the previously supplied fuel element is burned off.

Furthermore, an air mass sensor for measuring the air mass flow through the combustion air duct, which is connected to the control circuit, can preferably be provided. Depending on the measured values of the air mass sensor, the position of the combustion air flap can be regulated, wherein the desired combustion power can be set.

The invention will be explained in more detail with reference to an embodiment schematically illustrated in the drawing. 1 shows a front view of a furnace for burning solid fuel elements, FIG. 2 shows a section according to line II-II of FIG. 1, FIG. 3 shows a section according to line III-III of FIG FIGS. 5a and 5b show a detail view of the inlet flap control, FIGS. 6a and 6b show a detailed view of the firing element control, and FIGS. 7a and 7b show a detailed view of the air flap control.

In Fig.l is denoted by 1 a furnace having a combustion chamber and a supply chamber 3 shown in Fig.2. Furthermore, a grate 4 is provided, on which a schematically with 5 indicated solid fuel element rests. As can be seen in particular from the cross-sectional view according to FIG. 2, a feed device 6 in the form of a lock is arranged between the storage space 3 and the combustion space 2, wherein the feed device has a drum 8 which can be driven to rotate about the axis 7. The operation of the fuel supply will be explained in more detail with reference to Figure 4 in the sequence.

2, a combustion air duct 9 opening into the combustion chamber 2 is provided, wherein an air mass sensor 10 measures the quantity of air flowing through the combustion air duct 9. The flow cross-section of the combustion air duct 9 determines a combustion air flap 11, which is pivotally mounted about an axis 12 and has an actuating lever 13. The actuating lever 13 cooperates with a control stop 14 on a control disk 15, so that the control can take place in a manner as will be explained in the following with reference to the detailed illustration in FIG.

Below the grate 4, an ignition device 16 is pivotally mounted, wherein the pivot axis is again denoted by 12 and coincides with the pivot axis for the pivoting of the combustion air flap 11. For pivoting the ignition device 16, in turn, an actuating lever 17 is provided, which also cooperates with the control stop 14.

2, an inlet flap 18 can also be seen, which separates the combustion chamber 2 from the reservoir 3 and which is arranged pivotable about an axis 19. For actuating the inlet flap, an actuating arm 20 is arranged, which can be brought into operative connection with a control stop 21 of the control disk 15, as will be explained in more detail with reference to FIG.

In Figure 3, the same reference numerals have been retained for the same parts and it is additionally a motor 22 can be seen, the the drum 8 and the rotatably connected to the drum 8 control disk 15 to rotate about the axis 7 drives. The engine 22 is just like the air mass sensor 10, a combustion chamber sensor, not shown, and a room temperature sensor connected to a control circuit which controls the drive motor 22.

4a to 4g, the sequence of feeding a fuel element 5 from the storage space 3 into the combustion chamber 2 is now shown schematically. 4a, the fuel element 5 to be supplied is still completely in the storage space 3. In this case, the fuel element 5 is stopped by the jacket of the drum 8, so that it initially remains in its original position in the storage space 3. After a rotation of the drum 8 according to the arrow 23 over a first angle, the fuel element 5 now passes into the region of the recess 24 in the shell of the drum 8, wherein it can be seen that in the embodiment shown here, the drum shell extends only over a circumference of a three-quarter circle so that the recess 24 extends over the circumference of a quarter circle. The recess 24 is in this case dimensioned and adapted to the diameter of the supplied fuel element 5, that only a single fuel element 5 can be accommodated.

As shown in Figures 4c and 4d, the fuel element to be supplied 5 is added during the further rotation of the drum 8 according to the arrow 23 in the recess 24 so that it is transported further in the feed direction, which from the illustrations in the Fig.4d and FIG. 4e shows that another fuel element 25 is subsequently stopped by the shell of the drum 8, so that it remains in the storage space 3. After another rotation results in the position shown in Figure 4f, so that the fuel element 5, as can be seen from Figure 4g, can emerge in the sequence of the recess 24 in the drum 8 and along the downwardly inclined bottom 26 of the feeder on the rust 4 can roll down. After burning off the fuel element

5, a further feeding operation can be started, for which purpose the sequence according to FIGS. 4a to 4g is repeated.

It can be seen from the illustration according to FIGS. 5a and 5b how the inlet flap 18 is actuated during the feeding process. For this purpose, the inlet flap 18 has an actuating arm 20, which interacts with a control stop 21 during the rotation of the control disk 15. In this case, the starting position is shown in Fig.5a, in which the inlet flap

18 is closed, in Figure 5b the position in which the inlet flap 18 is opened. In Figure 5b it can be seen that the control stop 21 has taken during the rotation of the control disk 15 according to the arrow 23, the actuating arm 20 by a predetermined angle in the direction of rotation, so that the inlet flap 18 by pivoting about the pivot axis

19 was opened. The control stop 21 is in this case arranged on the control disk 15 such that the inlet flap 18 is opened at a time just before the feed drum 8 releases the fuel element 5, ie approximately in a region as shown in FIGS. 4e and 4f.

In FIGS. 5a and 5b, it can further be seen that the control disk 15 has two markings or protrusions 27 and 28 whose presence is detected by the stationary inductive sensors 29 and 30. The sensors 29 and 30 are in this case connected to a control circuit, not shown, wherein, for example, in the position shown in Figure 5a both the sensor 29 and the sensor 30 signals the presence of the projections 27 and 28, wherein such a signal means that the inlet flap 18 is closed.

The detailed illustration in FIGS. 6a and 6b shows the control of the ignition element 16. The Zündelelement 16 is fixed to a pivotable about the pivot axis 12 lever, wherein the actuating arm is denoted by 17. The actuating arm cooperates with a control stop 14 which is attached to the control disk 15. During the rotation of the control disk in the direction of arrow 23, the control stop 14 takes the actuating arm 17, so that the ignition element 16 is pivoted in the direction of arrow 31 in the position shown in Figure 6a to the grate 4 and thus below the fuel element 5. In this position, the fuel element 5 can be ignited by the ignition element 16. After a further rotation of the control disk 15 in the position shown in Figure 6b, the ignition element 16 can be pivoted away by gravity back to the original position in which it is stored at a greater distance from the grate 4 to destruction due to the large To avoid heat during the burning of the solid fuel element 5.

Finally, FIGS. 7a and 7b show the control of the combustion air flap 11, which is pivotably mounted about the pivot axis 12. For actuation, a lever 13 is provided, which cooperates with the control stop 14, wherein a similar control as in Figure 6 was described with reference to the ignition element results. In the position shown in FIG. 7a, in which the control stop 14 has taken the actuating arm 13, the air flap 11 is open, so that the largest possible flow cross-section remains free in the air duct 9. Starting from the position shown in FIG. 7a, after a further rotation in the direction of the arrow 23, the air flap can be swiveled back into the position shown in FIG. 7b due to the dead weight of the flap 11. In this case, each position between the position shown in Figure 7a and in Figure 7b can be assumed and maintained during the combustion process by the control disk 15 is stopped in the respective desired intermediate position to adjust the respective desired flow cross-section. Zusainmenfassend the device of the invention is characterized by a very simple structure, with a single engine controls all the essential processes, namely the fuel supply, the pivoting and retracting of the ignition element, the opening and closing of the inlet flap and the control of the combustion air damper.

The operation of the device is preferably as follows. When the room temperature measured by the room temperature sensor is lower than the preset target room temperature, the oven starts to operate. The chimney draft is checked by means of the air mass sensor and it is determined whether a take-off is permitted. A combustion air blower for poor draft conditions of the chimney can be optionally controlled before the regulation. During the feeding of a fuel element, the flap and the combustion air flap are automatically opened. After the fuel element has entered the combustion chamber, the previously swiveled ignition element is turned on. The combustion chamber temperature sensor detects whether the fuel element is burning. When the fuel element burns, the ignition element is swung out. The air mass sensor measures the combustion air and the combustion air damper is adjusted to the desired combustion performance. About the temperature sensor in the combustion chamber, the end of the burn-up of the fuel element is detected and the combustion air damper is closed. If, due to the room temperature sensor, a further burning pass is subsequently required, it will be started. In this case, the next fuel element is ignited by the remains of debris without turning on the ignition element. Otherwise, another firing will only take place after the room temperature has fallen below the setpoint.

Claims

Claims:

1. A device for burning solid fuel elements, in particular of elongated fuel compacts having a round or polygonal cross section with at least five corners, comprising a combustion chamber and a storage space for Vorgätighalten a plurality of fuel elements, characterized by a fuel supply for automatically supplying each of a fuel element (5) from the Reservoir (3) in the combustion chamber (2).

2. Apparatus according to claim 1, characterized in that the fuel feed a lock for detecting and transporting a single fuel element (5) while retaining other fuel elements (25) summarizes.

3. Apparatus according to claim 1 or 2, characterized in that the lock of a rotatably drivable drum (8) is formed, whose jacket has a recess (24) for detecting a Brennstoffelelements (5) during rotation.

4. Apparatus according to claim 1 or 2, characterized in that the lock is formed by a rotatable drivable roller having a substantially kreissektorförmigem cross-section, wherein the circular sector has a central angle of 240 - 300 °, in particular 270 °.

5. Apparatus according to claim 4, characterized in that the roller is formed of a plurality of substantially kreissektor- shaped, parallel lamellae, which pass through corresponding slots of a downwardly inclined bottom of the feeder.

6. Device according to one of claims 1 to 5, characterized in that the fuel supply has a direction towards the Bennraum (2) downwardly inclined ramp (26) which forms the bottom of the storage space (3).

7. Device according to one of claims 1 to 6, characterized in that between the storage space (3) and the combustion chamber (2) a pivotable inlet flap (18) is arranged, which preferably an actuating arm (20) for pivoting the inlet flap (18). wearing.

8. Device according to one of claims 1 to 7, characterized in that in the combustion chamber (2) an ignition device (16) is provided.

9. Apparatus according to claim 8, characterized in that the ignition device (16) is arranged on a pivotable lever (17).

10. Device according to one of claims 1 to 9, characterized in that in the combustion chamber (2) emptying combustion air duct (9) having a flow cross-section determining combustion air damper (11) is provided.

11. The device according to claim 10, characterized in that the combustion air flap (11) is pivotally mounted and carries an actuating arm (13) for pivoting the combustion air flap (11).

12. Device according to one of claims 1 to 11, characterized in that a control device for controlling the movement of the inlet flap (18) and / or the combustion air flap (11) and / or the ignition device (16) is provided.

13. The apparatus according to claim 12, characterized in that the control device rotatably driven control member, in particular control disc (15), with control stops (14,21) which during movement with the actuating arm (20) for the inlet flap (18) and / or the pivot lever (17) of the ignition device (16) and / or the actuating arm (13) of the combustion air flap (11 ) can be brought into operative connection.

14. The apparatus according to claim 13, characterized in that the control member with the supply device, in particular drum (8) or roller, coupled, in particular fixed to this and is rotatable together with this.

15. The apparatus of claim 13 or 14, characterized in that the control disc (15) carries two control stops (21), wherein the one control stop (21) with the actuating arm (20) for the inlet flap (18) and the other control stop (14 ) can be brought into operative connection with the pivot lever (17) of the ignition device (16) and the actuating arm (13) of the combustion air flap (11).

16. The apparatus of claim 13, 14 or 15, characterized in that the control stops are designed as a cam (s).

17. Device according to one of claims 13 to 16, characterized in that the control disk (15) carries markings which are detectable by sensors (29,30).

18. The apparatus according to claim 17, characterized in that the markings of projections (27,28) are formed, which are detectable by inductive sensors (29,30).

19. Device according to one of claims 1 to 18, characterized in that a control circuit is provided which is connected to the drive of the feed device.

20. The apparatus according to claim 19, characterized in that the sensors (29,30) connected to the control circuit are, so that the drive of the feeder is driven in response to the sensor signals.

21. The apparatus of claim 19 or 20, characterized in that a combustion chamber temperature sensor is provided, which is connected to the control circuit.

22. The apparatus of claim 19, 20 or 21, characterized in that a room temperature sensor is provided, which is connected to the control circuit.

23. Device according to one of claims 19 to 22, characterized in that an air mass sensor (10) for measuring the air mass flow through the combustion air duct (9) is provided, which is connected to the control circuit.

24. Device according to one of claims 1 to 23, characterized in that the rotary drive for the lock of an electric motor (22) is formed.