DISTRIBUTION RING FOR FUEL IN A BURNER, BURNER HAVING SUCH A DISTRIBUTION RING AND DRYING DRUM HAVING SUCH A BURNER

Abstract

A distribution ring for fuel in a burner (7) includes a hollow body (21) which is configured to be annular with respect to a longitudinal axis (22), a feed spigot (23) which is connected to the hollow body (21) and is intended for feeding the fuel into the hollow body (21), and a plurality of discharge spigots (25) for discharging the fuel from the hollow body (21) to the burner (7). The discharge spigots (25) are each arranged externally at the hollow body (21) in the radial direction of the longitudinal axis (22).

Claims

1. A distribution ring for fuel in a burner, the distribution ring comprising: a hollow body which is configured to be annular with respect to a longitudinal axis; a feed spigot which is connected to the hollow body for feeding the fuel into the hollow body; and a plurality of discharge spigots which are configured to discharge fuel from the hollow body to the burner, wherein the discharge spigots are each arranged externally at the hollow body in a radial direction of the longitudinal axis.

2. A distribution ring according to claim 1, wherein the hollow body has a polygonal inner contour in a sectional plane containing the longitudinal axis, wherein an outer edge, oriented with respect to the radial direction, is oriented at least in sections parallel to the longitudinal axis.

3. A distribution ring according to claim 1, wherein the discharge spigots are spaced apart from each other in a circumferential direction with respect to the longitudinal axis.

4. A distribution ring according to claim 1, wherein the discharge spigots are uniformly spaced apart from each other in a circumferential direction with respect to the longitudinal axis.

5. A distribution ring according to claim 1, wherein the discharge spigots each have a spigot longitudinal axis which is arranged inclined with respect to the longitudinal axis at an angle of inclination (n), wherein 0° < n < 90°.

6. A distribution ring according to claim 5, wherein 15° < n < 75°.

7. A distribution ring according to claim 5, wherein 30° < n < 60°.

8. A distribution ring according to claim 5, wherein the spigot longitudinal axes of a plurality of discharge spigots intersect at one point.

9. A distribution ring according to claim 5, wherein the spigot longitudinal axes of each of the discharge spigots intersect at one point which is located on the longitudinal axis.

10. A distribution ring according to claim 1, further comprising a nozzle attachment detachably mounted on each of the discharge spigots.

11. A distribution ring according to claim 1, wherein the hollow body has an axial extension that is oriented parallel to the longitudinal axis and is variable in a circumferential direction with respect to the longitudinal axis.

12. A distribution ring according to claim 11, wherein the axial extension is at a maximum at an opening point of the feed spigot into the hollow body.

13. A distribution ring according to claim 11, wherein the axial extension decreases in a conveying direction of the fuel.

14. A distribution ring according to claim 11, wherein the axial extension decreases continuously in a conveying direction of the fuel.

15. A burner comprising: an air supply; a fuel feed; and a distribution ring connected to the fuel feed, the distribution ring comprising: a hollow body which is configured to be annular with respect to a longitudinal axis; a feed spigot which is connected to the hollow body for feeding the fuel into the hollow body; and a plurality of discharge spigots which are configured to discharge fuel from the hollow body to the burner, wherein the discharge spigots are each arranged externally at the hollow body in a radial direction of the longitudinal axis.

16. A burner according to claim 15, wherein the hollow body has a polygonal inner contour in a sectional plane containing the longitudinal axis, wherein an outer edge, oriented with respect to the radial direction, is oriented at least in sections parallel to the longitudinal axis.

17. A burner according to claim 15, wherein the discharge spigots each have a spigot longitudinal axis which is arranged inclined with respect to the longitudinal axis at an angle of inclination (n), wherein 0° < n < 90°.

18. A burner according to claim 15, wherein the distribution ring further comprises a nozzle attachment detachably mounted on each of the discharge spigots.

19. A burner according to claim 15, wherein the hollow body has an axial extension that is oriented parallel to the longitudinal axis and that varies in a circumferential direction with respect to the longitudinal axis.

20. A drying drum comprising a burner, the burner comprising: an air supply; a fuel feed; and a distribution ring connected to the fuel feed, the distribution ring comprising: a hollow body which is configured to be annular with respect to a longitudinal axis; a feed spigot which is connected to the hollow body for feeding the fuel into the hollow body; and a plurality of discharge spigots which are configured to discharge fuel from the hollow body to the burner, wherein the discharge spigots are each arranged externally at the hollow body in a radial direction of the longitudinal axis.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In the drawings:

[0027] FIG. 1 is a perspective, partially sectioned view of a drying drum with a burner having a distribution ring according to the invention;

[0028] FIG. 2 is a partially sectioned view according to section line II-II in FIG. 1;

[0029] FIG. 3 is an enlarged, partially sectioned view of the distribution ring on a burner head according to FIG. 1;

[0030] FIG. 4 is a view according to arrow IV in FIG. 3;

[0031] FIG. 5 is an enlarged detail view of detail V in FIG. 3;

[0032] FIG. 6 is a view according to arrow VI in FIG. 3;

[0033] FIG. 7 is a perspective view of the burner head with the distribution ring from behind;

[0034] FIG. 8 is a perspective view from the front corresponding to FIG. 7; and

[0035] FIG. 9 is a partially sectioned view according to arrow IX in FIG. 3.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0036] Referring to the drawings, an apparatus marked 1 in FIGS. 1 and 2 as a whole comprises a drying drum 3 which can be driven in rotation about an axis of rotation 2 for drying and/or heating material, in particular material for asphalt production, in particular rock material, old asphalt granulate and/or aggregates. The drying drum 3 is essentially configured to be hollow-cylindrical. The axis of rotation 2 is arranged with respect to the horizontal at an angle of inclination h which is in particular greater than 0° and in particular less than 10°, in particular less than 5° and in particular less than 3°.

[0037] As a result of the inclination of the drying drum 3, the material to be dried is conveyed in the drying drum 3 along a material conveying direction 4, which is oriented from left to right according to FIG. 1. A material outlet 6 is arranged at an end wall 5 of the drying drum 3, shown on the right in FIG. 1, by means of which material outlet 6 the dried material is discharged from the drying drum 3. The material outlet 6 can be arranged at different positions in the circumferential direction around the axis of rotation 2. It is also possible to arrange the material outlet 6 at a number of different positions.

[0038] A material inlet is arranged at a second end wall opposite the end wall 5, which is not shown in FIG. 1, in order to feed the material to be dried to the drying drum 3.

[0039] A burner 7 is arranged at the end wall 5 and in particular fastened to the end wall 5 and in particular integrated into the end wall 5. In particular, the end wall 5 has an opening through which the burner 7 is guided and projects at least partially into an interior space surrounded by the drying drum 3.

[0040] The burner 7 has a burner housing 9 having a burner longitudinal axis 8, which burner housing 9 can be arranged in particular parallel and in particular concentrically to the axis of rotation 2 at the end wall 5 of the drying drum 3. The burner housing 9 is essentially configured to be hollow-cylindrical and has an air supply 10 and a secondary fuel supply 11 for secondary fuel and/or for support fuel. The secondary fuel supply 11 comprises a secondary fuel source, in particular a secondary fuel storage container 12, which is connected to the burner 7 by means of a secondary fuel supply line 13.

[0041] Furthermore, a primary fuel supply line is connected to the burner 7, which primary fuel supply line has a primary fuel source 12a and a primary fuel supply line 13a connected thereto. For the sake of simplicity, the primary fuel source will be referred to as fuel source 12a and the primary fuel supply line as fuel supply line 13a in the following.

[0042] In the burner 7, in particular in the burner housing 9, a distribution ring 14 is arranged for the distributed supply of the fuel in the burner 7. The distribution ring 14 is connected to the fuel supply line 13a, which leads to the fuel source 12a. The distribution ring 14 is arranged, in particular concentrically to the burner longitudinal axis 8.

[0043] In addition, a further secondary fuel supply line is connected to the burner 7, which, like the secondary fuel supply line 11, serves to supply secondary fuel and/or support fuel. The further secondary fuel supply comprises a further secondary fuel storage container 12b, which is connected to the burner 7 by means of a further secondary fuel supply line 13b.

[0044] The burner 7 also has a pilot burner 37, which is shown purely schematically in FIG. 1. The pilot burner 37 is arranged inside the burner housing 9. The pilot burner 37 can be variably arranged in particular within the burner housing 9, in particular continuously or by means of a fastening device which specifies a number of discrete fastening positions. The variable arrangeability of the pilot burner 37 is in particular related to a direction parallel and/or radial and/or in circumferential direction with respect to the burner longitudinal axis 8. The pilot burner 37 is in particular fastened to an inner side of the burner housing 9. The pilot burner 37 serves to ignite a burner flame.

[0045] In operation, the burner 7 generates a burner flame that extends from the burner 7 into the interior space of the drying drum 3. By means of the burner 7 the heat is supplied along a heat supply direction 15 which is oriented opposite to the material conveying direction 4 according to FIG. 1. The drying drum 3 shown in FIG. 2 is operated in the counter-current method. It is understood that a configuration of the drying drum 3 is possible in which the material conveying direction 4 and the heat supply direction 15 are oriented in the same direction, i.e. the drying drum 3 is operated in the cocurrent method. A drying drum of this type is referred to as a parallel drum.

[0046] A swirling element 16 is arranged concentrically to the burner longitudinal axis 8. The swirling element 16 serves to swirl the air supplied by means of the air supply 10, in particular the sucked-in ambient air 10a, in particular in a tangential direction with respect to the burner longitudinal axis 8. The swirling element 16 can be configured as a baffle plate and in particular have a guide wheel. The swirling element 16 is configured in particular in such a manner that the sucked-in ambient air 10a is mixed with the supplied fuel, in particular solid fuel, and/or possible secondary fuel and/or support fuel in such a manner that the ignition properties and/or combustion properties of the mixture are improved and in particular optimized. The ignition properties and/or combustion properties are improved if the mixture has a high homogeneity. In particular, the mixture has a high homogeneity when a uniform and in particular a complete combustion of the fuel in the mixture takes place. A complete combustion can thus be controlled in particular by the fact that no more fuel components are contained in the exhaust gas current leaving the drying drum 3. During the operation of the drying drum 3, it may be necessary for the drying drum 3 to be operated at different operating points, wherein the different operating points can be accessed in a targeted manner by means of a system control.

[0047] In a plane perpendicular to the axis of rotation 2, the end wall 5 has an opening 38 which is essentially configured in the shape of a keyhole.

[0048] The opening 38 has an upper circular section in which the burner head 17 is arranged. An inner diameter of the circular section is larger than an out-er diameter of the burner head 17, so that a circumferential annular gap 39 results between the opening 38 and the burner head 17. The burner head 17 and the opening 38 are in particular arranged concentrically to each other and in particular each oriented concentrically with respect to the axis of rotation 2.

[0049] In a lower region, the circular section of the opening 38 passes into a U-shaped molding. The fuel supply line 13a is guided into the drying drum 3 through the U-shaped molding. The U-shaped molding has a circumferential gap with respect to the fuel supply line 13a. Correspondingly, there is an annular gap 39 running along the inner contour of the opening 38, in particular also along the U-shaped molding.

[0050] In the following, the distribution ring 14 is explained in more detail with reference to FIGS. 3 to 9.

[0051] The distribution ring 14 is arranged at a burner head 17 and integrated therein at least in sections. The burner head 17 is configured to be sleeve-shaped and has two cylinder sections 18, 19 that are arranged one behind the other along the burner longitudinal axis 8 and are connected to each other by means of a cone section 20. The burner head 17 is arranged in the burner 7 such that the first cylinder section 18 is arranged facing the air supply 10 and the second cylinder section 19 is arranged facing the drying drum 3. The first cylinder section 18 has a first inner diameter D.sub.i,1. The second cylinder section 19 has a second inner diameter D.sub.1,2, which is larger than the first inner diameter D.sub.i,1. In particular, the following applies: 1.0 .Math. D.sub.i,1 < D.sub.i,2 < 2.0 .Math. D.sub.i,1, in particular 1.05 • D.sub.i,1 < D.sub.i,2 < 1.5 • D.sub.i,1, in particular 1.1 • D.sub.i,1 < D.sub.i,2 < 1.3 • D.sub.i,1.

[0052] The distribution ring 14 serves for the distributed supply of the fuel, i.e. of fuel particles, in particular solid particles, into the burner 7, in particular into the burner head 17 and in particular into the second cylinder section 19.

[0053] The distribution ring 14 has a hollow body 21 which is annular with respect to a longitudinal axis 22 of the distribution ring 14. The distribution ring 14 is arranged concentrically at the burner head 17 and thus concentrically in the burner 7. This means that the longitudinal axis 22 and the burner longitudinal axis 8 coincide.

[0054] A feed spigot 23 is connected to the hollow body 21. In particular, the feed spigot 23 is integrally formed on the hollow body 21. The feed spigot 23 is in particular directly connected to the fuel supply line 13 and in particular connected thereto.

[0055] The feed spigot 23 is arranged eccentrically to the longitudinal axis 22. The feed spigot 23 extends away from the hollow body 21 along a radial direction relative to the longitudinal axis 22. In the region of an opening point 24 of the feed spigot 23 into the hollow body 21, the feed spigot 23 has a curvature. As a result of the curvature, a fluid current supplied to the hollow body 21, in particular a fuel-particle-air mixture, is deflected. The fuel-air mixture initially flows in the feed spigot 23 along the radial direction R and is then deflected towards the opening point 24 in the tangential direction T as a result of the curvature and fed into the hollow body 21.

[0056] The hollow body 21 defines a substantially circular flow direction for the fuel particles around the longitudinal axis 22.

[0057] The hollow body 21 has a plurality of discharge spigots 25 through which the fuel is discharged to the burner 7 and in particular into the burner head 17. According to the embodiment example shown, the hollow body 21 has sixteen discharge spigots 25 which are arranged on the distribution ring 14 equally spaced apart from each other in the circumferential direction about the longitudinal axis 22. It is understood that more or less than sixteen discharge spigots 25 may be present and/or arranged at different distances from each other in the circumferential direction. According to the embodiment example shown, the discharge spigots 25 are all arranged on a common circular line around the longitudinal axis 22, i.e. each at an identical radial distance with respect to the longitudinal axis 22. It is also possible that individual discharge spigots 25 are arranged at different radial distances from the longitudinal axis 22.

[0058] According to the embodiment example shown, all discharge spigots 25 are of identical configuration. It is also possible that individual or all discharge spigots 25 are configured differently, in particular with regard to their geometry.

[0059] The discharge spigots 25 are each arranged externally at the hollow body 21 in the radial direction with respect to the longitudinal axis 22. This radially outward arrangement is evident in particular from the illustrations in FIGS. 3 and 5.

[0060] The hollow body 21 has a polygonal inner contour. According to the embodiment example shown, the inner contour is quadrangular. The inner contour has an outer edge 26 located on the outside with respect to the radial direction of the longitudinal axis 22 and an inner edge 27 located on the inside, which are connected to each other via two axial edges 28 and 29 that are spaced apart from each other in the axial direction. According to the embodiment example shown, the second axial edge 29, which is arranged in the region of the cone section 20 and is in particular defined by the second cone section 20, is arranged to be inclined with respect to a normal plane of the longitudinal axis 22. The first axial edge 28, which is arranged in particular in the region of the first cylinder section 18, is oriented in particular parallel to a normal plane of the longitudinal axis 22.

[0061] However, it is also conceivable that the two axial edges 28, 29 are orient-ed parallel to each other.

[0062] The discharge spigot 25 is directly connected to the hollow body 21 via a through-opening 30 in the cone section 20. The through-opening 30 is arranged at the hollow body 21 in such a manner that it is arranged out-side in the radial direction.

[0063] The discharge spigots 25 are each configured to be hollow-cylindrical and have a spigot longitudinal axis 31, which are each arranged inclined at an angle of inclination n with respect to the longitudinal axis 22. According to the embodiment example shown, the angle of inclination n is about 40°. It is understood that the angle of inclination n may vary, in particular depending on the position of the respective discharge spigot 25 and in particular depending on the number of discharge spigots 25. Additionally, or alternatively, the angle of inclination n may also vary in dependence on the fuel used, in particular the solid fuel used, and in particular in dependence on a combination of different fuels. It is particularly advantageous if the angle of inclination n is identical for each discharge spigot 25 and the spigot longitudinal axes 31 intersect at a point P which is located on the longitudinal axis 22.

[0064] In particular, in each case one spigot longitudinal axis 31 is arranged in a common radial plane with the longitudinal axis 22. If, as in the embodiment shown, an even number of discharge spigots 25 are provided and in each case two discharge spigots 25 are arranged diametrically opposite each other with respect to the longitudinal axis 22, the spigot longitudinal axes 31 of the opposite discharge spigots 25 are arranged together with the longitudinal axis 22 in a common radial plane.

[0065] As can be seen in particular from FIG. 5, a nozzle attachment 32 is arranged at each discharge spigot 25 and in particular is placed onto each discharge spigot 25. The nozzle attachment 32 enables in particular a targeted and directed fuel supply. The nozzle attachment 32 has a slip-on section whose inner contour corresponds to an outer contour of the dis-charge spigot 25. In addition, the slip-on section is configured with an axial shoulder which serves as an axial stop along the spigot longitudinal axis 31. For fastening, in particular in the axial direction with respect to the spigot longitudinal axis 31, the nozzle attachment 32 has a transverse bore into which a retaining screw 33 is screwed and which serves to clamp the nozzle attachment 32 to the discharge spigot 25. The nozzle attachment 32 is optional and can also be omitted, in particular depending on the properties of the fuel used.

[0066] The nozzle attachment 32 is guided through a corresponding opening in a cone cover 34 in the burner head 17. An annular air gap 32a is formed between the outside of the nozzle attachment 32 and the opening. Air, in particular sucked-in ambient air 10a, can flow through the air gap 32a from the annular space between the cone section 20 and the cone cover 34 to the burner flame. It is advantageous if the air gap 32a is configured depending on the geometry of the nozzle attachment 32 and/or the opening in the cone cover 34 in such a manner that the flame geometry is un-disturbed by means of the air flowing in through the air gap 32a. The cone cover 34 is oriented substantially parallel to the cone section 20 of the burner head 17. In particular, the opening in the cone cover 34 is configured in such a manner that accessibility to the retaining screw 33 from the interior space of the burner head 17 is possible.

[0067] The nozzle attachment 32 serves in particular to guide the fuel, in particular the solid fuel, through the cone cover 34. If no nozzle attachment 32 is arranged at the discharge spigot 25, the resulting air gap 32a is configured in such a manner that the flame geometry is not permanently disturbed by inflowing air, in particular sucked-in ambient air 10a.

[0068] The distribution ring 14 has an axial extension which is oriented parallel to the longitudinal axis 22. The axial extension is defined by the distance between the axial edges 28, 29. If, as in the present embodiment example, the axial edges 28, 29 are oriented at different angles of inclination to each other, the axial extension results as an average value between a maximum axial extension and a minimum axial extension. In the embodiment example shown, the maximum axial extension is given at the outer edge 26 and the minimum axial extension at the inner edge 27.

[0069] According to the embodiment example shown, the axial extension is at a maximum at the opening point 24 and decreases in the conveying direction of the fuel, i.e. from the feed spigot 23, in particular in the circumferential direction around the longitudinal axis 22, towards the discharge spigots 25. In particular, the axial extension decreases continuously along the conveying direction and in particular linearly. This ensures that the fuel is automatically conveyed in the axial direction, i.e. towards the discharge spigots 25. The discharge of the fuel from the hollow body 21 via the discharge spigots 25 is thus evenly distributed and thus improved.

[0070] The circumferentially reducing axial extension a is in particular evident from the top view onto the burner head 17 in FIG. 6. A first axial extension a1 marked in FIG. 6 bottom is greater than a second axial extension a2 marked in FIG. 6 top. The reason for this is that the rear side wall 36, which defines the first axial edge 28, is arranged to be inclined with respect to a normal plane of the longitudinal axis 22. The greater the inclination of the side wall 36 with respect to the normal plane, the greater the axial conveyance of the fuel particles. In particular, the rear side wall 36 is configured to be helical.

[0071] The operation of the burner 7 and in particular the distribution ring 14 is explained in more detail below. The burner 7 is operated to supply heat to the drying drum 3. For this purpose, in particular sucked-in ambient air 10a is fed to the burner 7 via the air supply 10, and fuel, in particular sol-id fuel particles, is fed to the burner 7 via the primary fuel supply 12a, 13a. If necessary, further fuel, in particular secondary fuel and/or support fuel, can be supplied from the at least one secondary fuel source 12, 12b via the at least one secondary fuel supply 13, 13b. By means of the swirling element 16 and the distribution ring 14, an advantageous fuel-air mixture is generated in the burner head 17, which mixture is ignited by means of a pilot burner 37 and a burner flame is produced.

[0072] Depending on the property of the solid fuel, it may be necessary for the pilot burner 37 to first ignite a supporting flame that is created from a secondary fuel before the solid fuel, i.e. the primary fuel, is ignited. For the ignition of the supporting flame, the secondary fuel flows into the burner 7 via the secondary fuel supply lines 13, 13b.

[0073] The fuel particles are fed via the distribution ring 14 starting from the fuel source 12a via the fuel supply line 13a, which is connected to the feed spigot 23. From there, the fuel particle-air mixture is deflected from a radial current R into a tangential current T and fed into the hollow body 21. The corresponding flow arrows 35 are shown in FIG. 4. In the hollow body 21, the fuel particles flow essentially in the circumferential direction around the longitudinal axis 22.

[0074] This circumferential current is superimposed by an axial current proportion, i.e. a flow direction along the longitudinal axis 22 towards the dis-charge spigots 25. This axial current proportion is caused by the continuously decreasing axial extension of the hollow body 21.

[0075] As a result of the centrifugal forces acting on the current particles in the hollow body 21, the fuel particles are moved towards the outer edge 26 in the hollow body 21. Due to the fact that the discharge spigots 25 are arranged in the region of the outer edge 26 of the hollow body 21, the fuel particles can be discharged, in particular automatically and in particular without residue, from the hollow body 21 via the discharge spigots 25 into the burner head 17 towards the burner flame. Blocking or clogging of the discharge spigots 25 is avoided.

[0076] While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.