AT505521B1 - DEVICE FOR BURNING SOLID FUEL ELEMENTS - Google Patents

Description

Austrian Patent Office AT 505 521 B1 2009-11-15

Description: 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, a reservoir for holding a plurality of fuel elements and a fuel supply for automatically feeding each of a fuel element the storage space into the combustion chamber, wherein the fuel supply comprises a lock for detecting and transporting a single fuel element while retaining other fuel elements, which is preferably formed by a rotatably drivable drum whose shell has a recess for detecting a fuel element during rotation.

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 Flolzresten, such as Flobelspänen, under high pressure and without the addition of binders to 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 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 Vorrätigaltung the wood pellets takes place in large burners in silos, 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 an alternative to wood pellets, as already mentioned, larger solid fuels in the form of briquettes become known, with their 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 another compact is supplied only after 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 a 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 for automatically supplying a respective fuel element from the reservoir is provided in the combustion chamber, wherein the fuel supply a lock for detecting and transporting a single fuel element with simultaneous retention of further fuel elements, which is preferably formed by a rotatably drivable drum whose shell has a recess for detecting a fuel element during rotation, a control device for controlling the movement of an arranged between the reservoir and the combustion chamber inlet flap, one of the flow cross-section in a combustion air flap defining the combustion chamber and / or an ignition device provided in the combustion chamber is provided, which comprises a supply device, in particular a drum, f has set and with this jointly movable, in particular rotatable, control member, in particular control disk, with control stops.

Characterized in that an automatic fuel supply is installed in the oven, the manual refilling 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 design is 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.

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 recess formed in the shell of the drum can here be adapted to the cross section of the fuel elements to be fed, so that in fact certainly only a single fuel element is supplied, wherein the fuel supply includes a lock for detecting and transporting a single fuel element while retaining other fuel elements, the is preferably formed by a rotatably drivable drum whose shell has a recess for detecting a fuel element during rotation, wherein a control device for controlling the movement of an arranged between the reservoir and the combustion chamber inlet flap, one of the flow cross-section in a combustion chamber opening into the combustion chamber combustion channel Combustion air damper and / or provided in the combustion chamber ignition device is provided, the one on the supply device, in particular drum, fixed and with this g emeinsam movable, in particular rotatable, control member, in particular control disk, having control stops.

In order to facilitate the supply of a fuel element from the storage space into the combustion chamber is pivotally mounted according to a combustion air damper and carry an actuating arm for pivoting the combustion air damper, so that the flow cross-section of the combustion air duct can be adjusted in a simple manner by operating the lever ,

Thus, not only the supply of the fuel elements but in the consequence also the control of the amount of combustion air and the actuation of the ignition device can automatically take place, according to a preferred embodiment of a Control device for controlling the movement of the inlet flap, the combustion air damper and / or the ignition device provided. In this case, the control device may have a fixed to the drum and rotatable together with this control disk with Steueranschlagen, which are brought into operative connection during rotation with the actuating arm for the inlet flap, 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 a control stop with the actuating arm for the inlet flap and the other control stop can be brought into operative connection with the pivot lever of the ignition device and the actuating arm of the combustion air flap, so that with a number of only two control stops or control 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 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, i. As the drum rotates, the sensors check 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 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 has been burned off.

Furthermore, an air mass sensor for measuring the air mass flow through the combustion air duct may be provided, which is connected to the control circuit. 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 the line II-II of FIG. 1, FIG. 3 shows a section according to the line III-III of FIG. 1, FIG. 4a FIGS. 5a and 5b show a detail view of the inlet flap control, FIGS. 6a and 6b show a detailed view of the ignition element control, and FIGS. 7a and 7b show a detailed view of the air flap control.

In Fig. 1, 1 denotes 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, the feed device having 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 FIG. 4 in the sequence.

2, a combustion air duct 9 opening into the combustion chamber 2 is further provided, wherein an air mass sensor 10 measures the amount 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. 7.

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.

In Fig. 2 is further an inlet flap 18 can be seen, which separates the combustion chamber 2 from the storage space 3 and which is arranged pivotably 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. 5.

In Fig. 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 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 flow of the supply of a fuel element 5 from the storage space 3 in the combustion chamber 2 is now shown schematically. In Fig. 4a, the supplied fuel element 5 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 such that the recess 24 extends over the circumference of a quadrant of the Austrian patent office AT 505 521 B1 2009-11-15. 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 to be supplied 5 is received 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 is apparent from the representations in the 4d and 4e shows that a further fuel element 25 is stopped in the sequence by the jacket of the drum 8, so that it remains in the storage space 3. After a further rotation results in the position shown in Fig. 4f, so that the fuel element 5, as can be seen from Fig. 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 can roll down 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. 5 a shows the starting position in which the inlet flap 18 is closed, in FIG. 5 b the position in which the inlet flap 18 is open. In Fig. 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 has been opened by pivoting about the pivot axis 19. The control stop 21 is in this case arranged on the control disk 15, that the inlet flap 18 is opened at a time just before the feed drum 8, the fuel element 5 releases, that is approximately in a range as shown in Figs. 4e and 4f.

5a and 5b is further apparent that the control disk 15 has two markings or projections 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 Fig. 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.

From the detailed illustration in FIGS. 6a and 6b, the control of the Zündelelements 16 emerges. 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 Fig. 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 Fig. 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, in FIGS. 7a and 7b, the control of the combustion air flap 11 can be seen, which is mounted pivotably 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 Fig. 6 has been 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 in the air duct 9 remains free. Starting from the position shown in Fig. 7a is after a wide- 5/12

Claims (15)

Austrian Patent Office AT 505 521 B1 2009-11-15 rotation in the direction of arrow 23, a Rückverschwenkung the air damper in the position shown in Fig. 7b due to the dead weight of the flap 11 possible. In this case, each position between the position shown in Fig. 7a and in Fig. 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, with a single engine controls all the essential processes, namely the fuel supply, the pivoting and pivoting 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 carried out 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. 1. Apparatus 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, a storage space for Vorgätighalten a plurality of fuel elements and a fuel supply for automatically supplying a respective fuel element (5) from the storage space (3) in the combustion chamber (2), wherein the fuel supply comprises a lock for detecting and transporting a single fuel element (5) while retaining other fuel elements (25), which is preferably formed by a rotatably drivable drum (8), the jacket thereof a recess (24) for detecting a fuel element (5) during rotation, characterized in that a control device for controlling the movement of between the reservoir (3) and the combustion chamber (2) arranged inlet flap (18), one of the flow Cross section is provided in a combustion air flap (11) which determines the combustion chamber (9) and / or an ignition device (16) which is provided in the combustion chamber and which is fixed to the supply device, in particular the drum (8) and common thereto having movable, in particular rotatable, control member, in particular control disk (15), with control stops (14,21). 2. Apparatus according to claim 1, 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). 3. Apparatus according to claim 1 or 2, characterized in that the inlet flap (18) carries an actuating arm (20) for pivoting the inlet flap (18). 4. Device according to one of claims 1 to 3, characterized in that the ignition is arranged (16) on a pivotable lever (17). 5. Device according to one of claims 1 to 4, characterized in that the combustion air flap (11) is pivotally mounted and carries an actuating arm (13) for pivoting the combustion air flap (11). 6. Device according to one of claims 1 to 5, characterized in that the control stops (14, 21) during movement with the actuating arm (20) for the inlet flap (18), 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. 7. Device according to one of claims 1 to 6, 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 flap (11) can be brought into operative connection. 8. Device according to one of claims 1 to 7, characterized in that the control disk (15) carries markings which are detectable by sensors (29,30). 9. Apparatus according to claim 8, characterized in that the markings of projections (27,28) are formed, which are detectable by inductive sensors (29,30). 10. The device according to claim 8, characterized in that a control circuit is provided which is connected to the drive of the feed device. 11. Device according to one of claims 8 to 10, 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. 12. Device according to one of claims 1 to 11, characterized in that a combustion chamber temperature sensor is provided, which is connected to the control circuit. 13. Device according to one of claims 1 to 12, characterized in that a room temperature sensor is provided, which is connected to the control circuit. 14. Device according to one of claims 1 to 13, 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. 15. Device according to one of claims 1 to 14, characterized in that the rotary drive for the drum (8) by an electric motor (22) is formed. For this 5 sheets drawings 7/12