AT505521A1 - DEVICE FOR BURNING SOLID FUEL ELEMENTS - Google Patents

Description

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The invention relates to a device for burning solid fuel elements, in particular 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.

Solid fuel elements have become known in particular in the form of fuel compacts. 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 insert firing works in a similar way to the underfeed firing, except that the fuel is pushed from the side onto the firing plate via a screw conveyor. In the case of the roller grate system, on the other hand, the pellets fall from above onto several slowly rotating ones

Steel discs with a small gap. 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 pellets, for example, have a diameter of about 80-90 mm and a length of about 300 mm, the combustion device are usually fed individually, with another compact is supplied only after the burning of the previously supplied pressing. 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 above for burning solid fuel elements, in particular elongated fuel compacts with round or polygonal cross-section to the effect that the feed with the fuel pellets is simplified. * ♦ ···· f ··· ·· ff •······················································································· · # · «| | -3-

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 feed is installed in the oven, the doggy 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 Berenn-material element during rotation. The recess formed in the jacket of the drum can in this case be adapted to the cross-section of the fuel elements to be supplied, so that in fact only a single fuel element is actually supplied in each case.

In order to facilitate the supply of a fuel element from the storage space into the combustion space, it is provided according to a preferred development that the fuel supply line has a ramp inclined downwards in the direction of the clearance space. It 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 Verschwen-ken the inlet flap. With the aid of the actuating arm, the inlet flap can in this case be opened and closed in a controlled manner, the inlet flap preferably being opened shortly before the fuel element passes from the storage space into the combustion chamber and shortly thereafter closed again in order 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. Here, the -5-

Combustion air damper be pivotally mounted and carry an actuating arm for pivoting the combustion air damper, so that by actuating the lever, the flow cross-section of the combustion air duct can be adjusted in a simple manner.

So that now not only the supply of the fuel elements but also the control of the amount of combustion air and the actuation of the ignition device can take place automated, according to a preferred embodiment, a control device for controlling the movement of the inlet flap, the combustion air damper and / or the ignition device is provided. In this case, the control device may have a defined on the drum and rotatable together with this control disc with control stops, which are brought into operative connection during rotation with the actuating arm for the inlet door, the pivot lever of the ignition device and / or the actuating arm of the combustion air damper. With such a design, during rotation of the drum, i. during delivery of a fuel element into the combustion chamber in a defined sequence actuation of the inlet flap, the igniter or the combustion air damper, so that the supply movement is directly coupled to the control of the inlet flap, the igniter 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 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 can be brought into operative connection, so that with a number of only two control stops or control - 6 cam all functions of the device according to the invention can be set in motion.

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 be able to solve 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 start position is not given, the control circuit will move the feeder first to the start position or even if this is not possible, an error message is output during the operation of the feeder, i. As the drum rotates, the sensors check for proper operation and stop operation, or issue 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 burn-up of a fuel element can be detected and the combustion I · «· · · · · · · · · · · ··· · · · · ·

- 7 air damper are closed, whereupon 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 rests a schematically indicated with 5 solid fuel element. 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. FIG the air flowing through the combustion air channel 9 measures air. The flow cross-section of the Verbrennungsluftka-nals 9 determines a combustion air damper 11 which is pivotally mounted about an axis 12 and an actuating lever 13 has. 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, which drives the drum 8 and the drum 8 rotatably connected control disk 15 to rotate about the axis 7. The engine 22, like the air mass sensor 10, a combustion chamber sensor, not shown, and a room temperature sensor are 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 FIGS. 4c and 4d, the fuel element 5 to be supplied during the further rotation of the drum 8 is received in the recess 24 in accordance with the arrow 23 in such a way that it is transported further in the feed direction, from the representations in FIGS 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 a further rotation results in the position shown in Figure 4f, so that the fuel element 5, as can be seen from Figure 4g, can occur in the sequence of the recess 24 in the drum 8 and along the downwardly inclined bottom 26 of the feeder can roll down on the grate 4. 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.

From the illustration according to FIGS. 5a and 5b, it can be seen 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. FIG. 5a shows the starting position in which the inlet flap 18 is closed, in FIG. 5b the position in which the inlet flap 18 is open. In Figure 5b it can be seen that the control stop 21 has during the rotation of the control disk 15 according to the arrow 23 the actuating arm 20 - 10 taken a predetermined angle in the direction of rotation, so that the inlet flap 18 was opened by pivoting about the pivot axis 19. 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 with 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 under 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. · · Μ 4 4 4 4 4 4 4 4 Finally, FIGS. 7a and 7b show the control of the combustion air flap 11, which is mounted so as to be pivotable 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 set the respective desired flow cross-section.

In summary, the device according to the invention is characterized by a very simple structure, wherein a single engine controls all essential processes, namely the fuel supply, the extension and retraction 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 damper 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 (20)

9 * «* • · ♦ • · · · · · · · · · · · 99 + 9 99 9 9 9 9 9 99 9 9 9 9 9 • 99 +99! 1. A device for burning solid fuel elements, in particular of elongated fuel compacts with round or polygonal cross section with at least five corners, comprising a combustion chamber and a storage space for Preserve a plurality of fuel elements, characterized by a fuel supply for automatically supplying a respective fuel element (5) from the storage space (3) in the combustion chamber (2). 2. Device according to claim 1, characterized in that the fuel supply comprises a lock for detecting and transporting a single fuel element (5) while retaining further fuel elements (25). 3. Apparatus according to claim 1 or 2, characterized in that the lock is formed by a rotatably drivable drum (8), whose jacket has a recess (24) for detecting a Brennstoffelelments (5) during rotation. 4. Apparatus according to claim 1, 2 or 3, 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). 5. Device according to one of claims 1 to 4, 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). 6. Device according to one of claims 1 to 5, characterized in that in the combustion chamber (2) an ignition device (16) is provided. 7. Device according to one of claims 1 to 6, characterized in that the ignition device (16) is arranged on a pivotable lever (17). 8. Device according to one of claims 1 to 7, characterized in that in the combustion chamber (2) emanating combustion air duct (9) having a Strömungsguerschnitt determining combustion air damper (11) is provided. 9. Device according to one of claims 1 to 8, characterized in that the combustion air flap (11) is pivotally mounted and carries an actuating arm (13) for pivoting the combustion air flap (11). 10. Device according to one of claims 1 to 9, characterized in that a control device for controlling the movement of the inlet flap (18), the combustion air damper (11) and / or the ignition device (16) is provided. 11. Device according to one of claims 1 to 10, characterized in that the control device to the feed device, in particular drum (8), fixed and jointly movable with this, in particular rotatable, control member, in particular control disc (15), with control stops (14 , 21) which during operation are engageable with the actuating arm (20) for the inlet flap (18), the pivoting lever (17) of the firing device (16) and / or the actuating arm (13) of the combustion air flap (11). 12. Device according to one of claims 1 to 11, 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) with the pivot lever (17) of the ignition device (16) and the actuating arm (13) of the combustion air damper (11) can be brought into operative connection. 13. Device according to one of claims 1 to 12, characterized in that the control disc (15) carries markings, which are detectable by sensors (29,30). 14. Device according to one of claims 1 to 13, characterized in that the markings of projections (27,28) are formed, which are detectable by inductive sensors (29,30). - 15- 15. Device according to one of claims 1 to 14, characterized in that a control circuit is provided, which is connected to the drive of the feed device. 16. Device according to one of claims 1 to 15, characterized in that the sensors (29,30) are connected to the control circuit, so that the drive of the feeding device is driven in response to the sensor signals. 17. Device according to one of claims 1 to 16, characterized in that a combustion chamber temperature sensor is provided, which is connected to the control circuit. 18. Device according to one of claims 1 to 17, characterized in that a room temperature sensor is provided, which is connected to the control circuit. 19. Device according to one of claims 1 to 18, 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. 20. Device according to one of claims 1 to 19, characterized in that the rotary drive for the drum (8) by an electric motor (22) is formed. Vienna, 14 August 2007 Applicants by: Haffn hmann godfather