U.S. patent application number 14/648824 was filed with the patent office on 2015-10-22 for burner tip and burner.
The applicant listed for this patent is SIEMENS AKTIENGESELLSCHAFT. Invention is credited to Christoph KIENER.
Application Number | 20150300634 14/648824 |
Document ID | / |
Family ID | 47602922 |
Filed Date | 2015-10-22 |
United States Patent
Application |
20150300634 |
Kind Code |
A1 |
KIENER; Christoph |
October 22, 2015 |
BURNER TIP AND BURNER
Abstract
A burner tip (1) having a burner outlet opening (3) and at least
one burner tip part (11) which surrounds the burner outlet opening
(3) and has a burner tip wall (11A) with an end wall (47, 67, 147)
forming a closed end of the burner tip part (11). The burner tip
part (11) has in its interior a hollow space extending to the end
wall (47), wherein the burner tip wall (11A) has an inner side
facing towards the hollow space. A displacement body (5) arranged
in the hollow space, has an outer side facing towards the inner
side of the burner tip wall (11A). At least one flow channel (10)
is formed between the inner side of the burner tip wall (11A) and
the outer side of the displacement body.
Inventors: |
KIENER; Christoph; (Munchen,
DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SIEMENS AKTIENGESELLSCHAFT |
Munchen |
|
DE |
|
|
Family ID: |
47602922 |
Appl. No.: |
14/648824 |
Filed: |
November 6, 2013 |
PCT Filed: |
November 6, 2013 |
PCT NO: |
PCT/EP2013/073108 |
371 Date: |
June 1, 2015 |
Current U.S.
Class: |
431/183 ;
110/297; 431/188 |
Current CPC
Class: |
F23D 14/78 20130101;
F23D 14/58 20130101; F23D 14/22 20130101; Y02E 20/34 20130101; F23D
2214/00 20130101; F23D 14/76 20130101; F23L 7/00 20130101; F23L
7/007 20130101; F23D 14/24 20130101 |
International
Class: |
F23D 14/24 20060101
F23D014/24; F23D 14/58 20060101 F23D014/58; F23L 7/00 20060101
F23L007/00; F23D 14/76 20060101 F23D014/76 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 14, 2012 |
EP |
12197202.0 |
Claims
1. A burner tip comprising: a burner discharge orifice; at least
one burner tip part configured to encompass the burner discharge
orifice, the tip part has a burner-tip wall with an end wall which
forms a closed end of the burner tip part, the burner tip part
includes an interior which has a cavity which reaches up to the end
wall, and the burner-tip wall has an inner side pointing towards
the cavity, a displacement body arranged in the cavity and having
an outer side facing the inner side of the burner-tip wall; at
least one flow passage between the inner side of the burner-tip
wall and the outer side of the displacement body, and the
displacement body is of hollow design.
2. The burner tip as claimed in claim 1, wherein the displacement
body has a near end, which is nearer to the end wall and a far end
which is further from the end wall and an interior space and, in
the region of the far end, at least one opening which opens towards
the interior space.
3. The burner tip as claimed in claim 2, further comprising: at
least one flow guiding element arranged in the displacement-body
opening and configured such that the guiding element divides the
displacement-body opening into an inflow section and an outflow
section and in such a way that a flow path is formed around the
flow guiding element between the inflow section and the outflow
section.
4. The burner tip as claimed in claim 2, further comprising: the
displacement body has at least one additional opening which is open
towards the interior space and is arranged between the near end of
the displacement body and the displacement-body opening which is
arranged in the region of the far end, and the displacement-body
interior space forms a flow path between the displacement-body
opening and the additional displacement-body opening.
5. The burner tip as claimed in claim 3, further comprising: a
collecting chamber located in and the displacement-body interior
space are moved, crossed out from original position and underlined
in new position, branching from the flow path, for receiving
foreign bodies separated out of a fluid flowing through the flow
path.
6. The burner tip as claimed in claim 5, further comprising: an
inlet for the collecting chamber located in a region of the flow
path having a change of flow direction.
7. The burner tip as claimed in claim 1, further comprising:
support structures connecting the displacement body to the inner
side of the burner-tip wall, the support structures extend from the
outer side of the displacement body to the inner side of the
burner-tip wall.
8. The burner tip as claimed in claim 7, further comprising: the
support structures comprise rib-like or pillar-like structures, and
adjacent rib-like or pillar-like structures which converge to form
arches on an outer side of the displacement body and/or on the
inner side of the burner-tip wall, at least in the region of the
end wall.
9. The burner tip as claimed in claim 8, wherein the arches are
pointed arches.
10. The burner tip as claimed in claim 7, wherein a density of the
support structures which connect the displacement body to the
burner-tip wall, is increased at least in the region of the end
wall in comparison to other regions of the burner-tip wall.
11. The burner tip as claimed in claim 10, further comprising:
where the density of the support structures is increased, the
burner-tip wall is of thinner design in comparison to regions
without increased density of support structures.
12. The burner tip as claimed in claim 7, wherein the displacement
body is formed in one piece with the support structures and the
burner-tip wall.
13. The burner tip as claimed in claim 7, wherein the burner-tip
wall is lined with a thermal barrier coating on its outer side, at
least in the region of the end wall.
14. The burner tip as claimed in claim 7, further comprising: swirl
vanes, which project at least partially into the burner discharge
orifice, are formed in one piece with the burner-tip wall.
15. The burner tip as claimed in claim 14, wherein the flow passage
between the inner side of the burner-tip wall and the outer side of
the displacement body extends at least partially through the swirl
vanes.
16. The burner tip as claimed in claim 14, wherein the swirl vanes
form a blading assembly which has the form of a nozzle which
reduces the flow cross section in specific regions of the blading
assembly configured for an oxygen-steam mixture flowing through the
blading assembly.
17. The burner tip as claimed in claim 7, wherein the burner tip
part and the displacement body are of toroidal design.
18. A burner with a burner tip as claimed in claim 1.
Description
[0001] The present invention relates to a burner tip, especially to
a burner tip for high-temperature applications in synthesis gas
production. In addition, the invention relates to a burner,
especially to a burner for synthesis gas production.
[0002] A burner for a synthesis gas reactor is described
schematically in DE 10 2008 006 572 A1. This comprises an outer
burner element, in the tip of which provision is made for a cavity
with a displacement body arranged therein. Guided around the
displacement body is a cooling water passage which serves for
cooling the burner tip. The burner also comprises an inner burner
element which is arranged concentrically to the outer tube. Formed
between the inner burner element and the outer burner element is a
passage for the feed of pulverized fuel, for example pulverized
coal. Also, the inner burner element, in the region of its tip, has
a cavity with a displacement body arranged therein, around which is
guided a cooling water passage by means of which the tip of the
inner burner element is cooled. A pilot burner is arranged
centrally to the inner burner element, wherein a feed passage for
an oxygen/steam mixture is formed between the inner burner element
and the pilot burner. Like the outer and the inner burner element
the pilot burner is of a hollow walled design, wherein a
displacement body is arranged in the region of the tip of the pilot
burner and around which is guided a cooling water passage in order
to be able to cool the pilot burner tip.
[0003] The tips of burners in synthesis gas reactors are subjected
to high temperatures during operation of the reactor so that a
considerable heat input into the burner tip takes place. The
inputted heat is dissipated by means of the cooling water flowing
in the described cooling water passages. In order to reduce the
heat input, the burner tip can also be provided with a thermal
barrier coating, as is described in DE 10 2008 006 572 A1.
[0004] The respective burner elements are as a rule constructed
from a plurality of tubes and a tip which interconnects the tubes
and in which is also arranged the displacement body. The tip in
this case is usually assembled from an outer annular part and an
inner annular part, wherein the outer annular part is connected to
the outer tube and the inner annular part is connected to the inner
tube. Moreover, the annular parts are welded together by their ends
facing away from the outer tube or the inner tube. The displacement
body is connected to a centrally arranged tube which divides the
interspace between the outer tube and the inner tube into an
annular feed passage for cooling water and an annular discharge
passage for cooling water. Each burner element therefore has a
complex construction. Furthermore, the burner tips are relatively
large, and therefore heavy, which reduces their manageability, for
example in the course of a maintenance.
[0005] For production engineering reasons, the wall thicknesses of
the tubes or of the tip parts are typically at least 3 mm, which
makes heat dissipation difficult and increases the susceptibility
to temperature fluctuations. Furthermore, suspended particles and
cooling water can lead over time to a constriction of the cooling
water passages in the region of the burner tip or even to blocking
of the cooling water passages, which entails an increased
maintenance requirement so that such constrictions can be
discovered in good time.
[0006] Moreover, the materials from which the burner tips are
produced are expensive and time consuming in processing since the
parts of which the burner tips consist have to be welded together.
The welding of the parts for forming the respective burner tip is
not simple since the typically used nickel-based superalloys
require special welding procedures.
[0007] Compared with the described prior art, it is the object of
the present invention to provide an advantageous burner tip,
especially for burner elements of a synthesis gas burner. In
addition, it is an object of the present invention to provide an
advantageous burner, especially for synthesis gas production.
[0008] The said object is achieved by a burner tip according to
claim 1 and a burner according to claim 18. The dependent claims
contain advantageous embodiments of the invention.
[0009] A burner tip according to the invention has a burner
discharge orifice and at least one burner tip part which
encompasses the burner discharge orifice. The burner tip part has a
burner-tip wall with an end wall which forms a closed end of the
burner tip part. In its interior, the burner tip part has a cavity
which reaches up to the end wall. The burner-tip wall has an inner
side pointing towards the cavity. A displacement body, with an
outer side facing the inner side of the burner-tip wall, is
arranged in the cavity, wherein the displacement body is of hollow
design. At least one flow passage is formed between the inner side
of the burner-tip wall and the outer side of the displacement
body.
[0010] As a result of the hollow design of the displacement body, a
saving can be made in weight and material in comparison to burner
tips according to the prior art in which the displacement body is
designed as a solid body. On account of the lower weight, the
burner tip, which can have diameters of 50 cm and more, is easier
to manage, for example in the course of a maintenance or repair
process.
[0011] In a development of the burner tip according to the
invention, the displacement body has a near end in relation to the
end wall, a far end in relation to the end wall, an interior space,
and, in the region of the far end, at least one opening which is
open towards the interior space. In this way, it becomes possible
to make the hollow displacement body accessible to a cooling fluid,
for example cooling water, flowing through the flow passage between
the outer side of the displacement body and the inner side of the
burner-tip wall. To this end, for example a flow guiding element
can be arranged in the displacement-body opening in such a way that
it divides the displacement-body opening into an inflow section and
an outflow section and in such a way that a flow path around the
flow guiding element is formed between the inflow section and the
outflow section. Alternatively, there is the possibility that the
displacement body has at least one additional opening which is open
towards the interior space. This is then arranged between the near
end of the displacement body and the displacement-body opening
which is arranged in the region of the far end. Between the
displacement-body opening and the additional displacement-body
opening, the displacement-body interior space forms a flow path for
cooling fluid, such as cooling water.
[0012] If a flow path for cooling fluid is formed inside the
displacement body, a collecting chamber, branching from the flow
path, for foreign bodies in the fluid flowing through said flow
path can be located in the displacement-body interior space. In
this case, it is advantageous if the collecting chamber in the
displacement-body interior space is located in a region of the flow
path in which a change of flow direction takes place. It is
especially advantageous if the change of flow direction entails a
substantial flow reversal. In this case, the space in the hollow
displacement body is sufficient in order to be able to provide an
adequately large collecting chamber. The collecting of foreign
bodies, such as suspended particles, in the cooling fluid leads to
the fluid passages leading around the outer side of the
displacement body blocking more slowly and as a result a
constriction of the flow cross section can be delayed for a longer
period. This in turn has a favorable effect upon the maintenance
intervals.
[0013] In a specific embodiment of the burner tip according to the
invention, the displacement body is connected to the inner side of
the burner-tip wall via support structures, for example via
rib-like or pillar like structures. The support structures in this
case extend from the outer side of the displacement body to the
inner side of the burner-tip wall. If the support structures are
designed as rib-like or pillar-like structures, adjacent rib-like
or pillar-like structures can converge to form arches on the outer
side of the displacement body and/or on the inner side of the
burner-tip wall, at least in the region of the burner tip end wall.
These arches can especially be designed as pointed arches similar
to the arches in gothic architecture. By means of the support
structures, the position of the displacement body inside the
burner-tip wall can be fixed. Furthermore, the entire structure
consisting of burner-tip wall and displacement body can be of an
altogether more stable design.
[0014] In a further embodiment of the burner tip with support
structures, the density of support structures, which connect the
displacement body to the burner-tip wall, is increased at least in
the region of the end wall in comparison to other regions of the
burner-tip wall. Where the density of the support structures is
increased, the burner-tip wall can then be of thinner design in
comparison to regions without increased density of support
structures. They can especially have thicknesses of below 3 mm,
especially thicknesses in the region of 0.5 mm to 2 mm. In this
way, in regions which are subjected to especially high temperatures
and/or to especially pronounced temperature fluctuations the heat
which is absorbed by the burner-tip wall can be dissipated more
rapidly to the cooling fluid, as a result of which the thinner wall
can be kept cooler than a thicker wall, which in turn has a
favorable effect upon the available operating period up to a
maintenance.
[0015] Within the scope of the burner tip according to the
invention, the displacement body can especially be formed in one
piece with the support structures and the burner-tip wall. This
allows a particularly stable structure and enables the production
with a large number of structures at the outset.
[0016] The production can in this case be carried out by means of
an additive manufacturing process, for example by means of
selective laser melting.
[0017] The burner-tip wall can be lined with a thermal barrier
coating, at least in the region of the end wall. In particular, if
the burner-tip wall has thicker and thinner regions, an embodiment
in which the thermal barrier coating is applied to the thinner
regions, especially in the region of the end wall, is advantageous.
Due to the fact that in this embodiment the burner-tip wall is
thinner in the regions with a thermal barrier coating, it can
achieve the effect of the entire wall thickness in these regions,
despite the applied thermal barrier coating, not exceeding the
thickness of the remaining regions without a thermal barrier
coating.
[0018] In the burner tip according to the invention, swirl vanes,
which project at least partially into the burner discharge orifice,
can also be formed in one piece with the burner-tip wall.
Previously, swirl vanes have been inserted from the burner side
facing away from the burner tip into the burner discharge orifice
which is encompassed by the burner-tip wall. With this insertion,
damage to the swirl vanes and/or to the burner tip wall can occur.
As a result of the one-piece design of the swirl vanes with the
burner-tip wall, the insertion of swirl vanes is superfluous.
Moreover, there is also the possibility that the flow passage which
is formed between the inner side of the burner-tip wall and the
outer side of the displacement body also extends at least partially
through the swirl vanes. In this way, a common cooling of burner
tip and swirl vanes is made possible.
[0019] With the aid of specific manufacturing processes (additive
manufacturing processes), it can achieve the effect of the swirl
vanes forming a blading assembly which has the form of a nozzle
which reduces the flow cross section in specific regions of the
blading assembly for an oxygen-steam mixture flowing through said
blading assembly.
[0020] In the burner tip according to the invention, the burner-tip
wall and the displacement body are of toroidal design.
[0021] A burner according to the invention is provided with a
burner tip according to the invention. The characteristics and
advantages associated therewith are gathered from those of the
burner tip according to the invention.
[0022] Further features, characteristics and advantages of the
present invention arise from the following description of exemplary
embodiments with reference to the attached figures.
[0023] FIG. 1 shows a schematic diagram of a burner, as is used in
synthesis gas reactors.
[0024] FIG. 2 shows the tip of a first burner element.
[0025] FIG. 3 shows the tip of a second burner element.
[0026] FIG. 4 shows the tip of pilot burner used in the burner.
[0027] FIG. 5 shows an alternative embodiment of the tip from FIG.
3.
[0028] FIG. 6 shows a further alternative embodiment of the tip
from FIG. 3.
[0029] FIG. 7 shows yet another alternative embodiment from FIG.
3.
[0030] FIG. 8 shows the embodiment from FIG. 7 in a section along
the line VIII-VIII.
[0031] The basic construction of a burner for synthesis gas
reactors is described below with reference to FIG. 1.
[0032] The burner is constructed in a rotationally symmetrical
manner around a burner axis A and comprises a tubular feed line
section and a burner tip 1 which is connected to the feed line
section and encompasses a burner orifice 3.
[0033] The burner comprises a first, outer burner element 2 which
in the tubular section of the burner is formed from three
inter-inserted tubes 4, 6, 8. Formed between the tubes are a
cooling fluid feed passage 7 and a cooling fluid discharge passage
9, via which cooling fluid can be fed to the burner tip 1 and
discharged from this respectively. As cooling fluid, water is
especially a consideration. In the region of the burner tip 1, the
outer burner element 2 deviates from the pure tubular shape and is
inclined in the direction towards the center of the burner
discharge orifice 3. Furthermore, in the region of the tip it has a
cavity in which a displacement body 5 is arranged at a distance
from the wall of the burner element 2 in this region. Formed in
this case between the inner side of the wall 11A of the burner
element 2 in the tip region and the outer side of the displacement
body is a flow passage 10 by means of which the cooling fluid, for
example water, is directed through the tip of the outer burner
element 2 in order to cool this.
[0034] The part of the outer burner element 2 which deviates from
the tubular shape constitutes an outer burner tip part 11 which is
formed as an independent part and the wall 11A of which is welded
to the tubular section of the outer burner element 2.
[0035] In this case, the wall 11A of the burner tip part 11 has an
approximately U-shaped bend so that it can be connected both to the
outer tube 4 and to the inner tube 8 of the tubular section of the
outer burner element 2. The displacement body 5 is fitted onto the
center tube 6. To this end, it has a groove 5A, the width of which
is adapted to the wall thickness of the center tube 6 of the
tubular section.
[0036] The burner furthermore comprises an inner burner element 12
which apart from in the region of the burner tip 1 is also formed
from three inter-inserted tubes 14, 16, 18. In the region of the
burner tip 1, an inner burner tip part 21, with a cavity located
therein, is connected to the tubular section of the inner burner
element 12. A displacement body 15 is arranged in this cavity,
wherein the outer side of the displacement body has a distance from
the inner side of the burner-tip wall 21A in the region of the
inner burner tip part 21 so that a flow passage is formed between
the two. The feed of cooling fluid into the flow passage is carried
out via a feed passage 17 which is formed between the
inter-inserted tubes 14, 16 of the tubular section of the inner
burner element 12, and the discharge of the cooling fluid from the
region of the inner burner tip part 21 is carried out via a
discharge passage 19 which is formed between the inter-inserted
tubes 16, 18. Also, the inner burner tip part is designed as an
independent part, the wall 21A of which is welded to the outer tube
14 and to the inner tube 18 of the tubular section. To this end,
the wall 21A in the widest sense is bent in a U-shaped manner so
that it can be welded both to the outer tube 14 and to the inner
tube 18 of the three inter-inserted tubes 14, 16, 18 of the tubular
section. The displacement body 15 is fitted onto the center tube 16
of the tubular section. To this end, it has a groove 15A, the width
of which is adapted to the wall thickness of the center tube
16.
[0037] The inner burner element 12 has an outside diameter which is
smaller than the inside diameter of the outer burner element 2 so
that an annular passage is formed between the two, serving for the
feed of a pulverized fuel, for example for the feed of pulverized
coal.
[0038] The inner burner element 12 encloses a largely cylindrical
chamber in which is arranged a pilot burner 22. This comprises a
tubular section 22A which is formed from three tubes 24, 26, 28 and
to which is connected a pilot burner tip part 31 in the region of
the burner tip 1. The pilot burner tip part 31 has a cavity in
which is arranged a displacement body 25, wherein the outer side of
the displacement body has a distance from the inner side of the
wall 31A of the pilot burner tip part 31 so that a flow passage 30
is formed between the two. As in the case of the outer burner
element 2 and in the case of the inner burner element 12, the wall
31A of the tip part 31 is welded to the tubular section. The wall
31A of the pilot burner tip part is bent in this case in the widest
sense in a U-shaped manner so that on one side it can be welded to
the outer tube 24 of the tubular section of the pilot burner 22 and
to the inner tube 28 of the tubular section of the pilot burner
22.
[0039] The displacement body 25 is fitted onto the center tube 26
of the tubular section. To this end, it has a groove 25A, the width
of which is adapted to the wall thickness of the center tube
26.
[0040] The tubular section of the pilot burner 22 has an outside
diameter which is smaller than the inside diameter of the inner
burner element 12 so that an oxygen/steam passage 23 is formed
between the two. This serves for the feed of water vapor which is
required in the synthesis gas reactor for converting pulverized
fuel into synthesis gas, and, if necessary, for the feed of oxygen
or air. For promoting the synthesis gas reaction, the supplied
water vapor, and, if necessary, the supplied oxygen or the supplied
air, is swirled in order to promote the synthesis gas reaction.
[0041] To this end, swirl vanes 32 are arranged in the region of
the burner tip 1 between the inner burner element 12 and the pilot
burner 22.
[0042] The pilot burner 22 encloses an essentially cylindrical
cavity in which are arranged an ignition burner and a device for
flame monitoring. These two elements are shown in only a greatly
schematized form in the figure and are grouped under the
designation 33.
[0043] FIG. 2 shows the construction of the outer burner tip part
11. Also to be seen are the inter-inserted tubes 4, 6, 8 of the
tubular section of the outer burner element 2. The outer burner tip
part 11 terminates in an end wall 34 which constitutes the end of
the outer burner tip part. A cavity, in which, as already
described, the displacement body 5 is located, is formed in the
outer burner tip part 11. This displacement body, as is shown in
FIG. 2, is of hollow design. It has a near end 36 in relation to
the end wall 34 and a far end 38 in relation to the end wall with a
groove 5A for fitting onto the center tube 6 of the tubular section
of the burner element. In the region of the far end 38, especially
directly in front of the groove 5A in the far end, provision is
made for a displacement-body opening 40 which is open towards the
interior space 42 of the hollow displacement body 5 so that the
interior space 42 is accessible through the displacement-body
opening 40. The burner-tip wall 11A, which is bent in an
approximately U-shaped manner, is connected both to the outer tube
4 and to the inner tube 8 of the tubular section of the outer
burner element 2, whereas the displacement body 5 is connected to
the center tube 6 of the tubular section of the outer burner
element 2 in such a way that the displacement-body opening 40 is
open towards the feed passage 7 which is formed between the outer
tube 4 and the center tube 6. The displacement-body interior space
42 is consequently fluidically connected to the feed passage 7 for
the cooling fluid.
[0044] The hollow displacement body 5, which consists in the main
of a relatively thin wall 44, is connected to the inner side of the
burner-tip wall 11A via support structures 46. These support
structures can be of rib-like or pillar-like design so that they
obstruct the flow in the flow passage 10 as little as possible and
possibly even guide the flow.
[0045] FIG. 3 shows the construction of the inner burner tip part
21 and the inter-inserted tubes 14, 16, 18, adjoining it, of the
tubular section of the inner burner element 12. The inner burner
tip part 21 has a wall 21A with an end wall 47 which forms the
closed end of the inner burner tip part 21. As has already been
described with reference to FIG. 1, a displacement body 15 is
located in the cavity of the inner burner tip part 21. This
displacement body in turn is itself of hollow design and has a wall
54 enclosing an interior space 52. Furthermore, the displacement
body 15 has a near end 48 in relation to the end wall 47 and a far
end 49 in relation to the end wall 47 with a groove 15A for fitting
onto the center tube 16 of the tubular section of the burner
element. Arranged in the region of the far end 49, especially
directly in front of the groove 15A in the far end, is a
displacement-body opening 50 via which the displacement-body
interior space 52 is accessible. The wall 21A of the inner burner
tip part 21 is bent in an approximately U-shaped manner, wherein
the ends of the burner-tip wall 21A are connected to the outer tube
14 of the tubular section of the inner burner element 12 and to its
inner tube 18. The displacement-body wall 54 is connected to the
center tube 16 of the tubular section of the inner burner element
12 so that the displacement-body opening 50 is open towards the
feed passage 17 formed between the outer tube 14 and the center
tube 16 of the tubular section of the inner burner element 12. In
this way, the displacement-body interior space 52 is fluidically
connected to the feed passage 17 for the cooling fluid. The
displacement-body wall 54 is connected via support structures,
which for example can be of rib-like or pillar-like design, to the
inner side of the burner-tip wall 21A so that a defined distance is
provided between the outer side of the displacement body and the
inner side of the burner-tip wall 21A in order to form the flow
passage 20. As in the case of the outer burner tip part, the
support structures can also be designed in such a way that they
guide the flow through the flow passage, but in any case they are
designed so that they obstruct the flow as little as possible.
[0046] Swirl vanes 32 are formed in one piece with the burner tip
part 21 of the inner burner element 12. The swirl vanes 32 are
hollow and have in each case an interior space 58 which via a
cooling fluid inlet opening 59 and a cooling fluid outlet opening
60 is fluidically connected to the flow passage 20 which leads
around the displacement body 15. The displacement-body interior
space 58 is therefore part of the cooling circuit so that the swirl
vanes 32 together with the inner burner tip part 21 are cooled by
the cooling fluid.
[0047] A tube 62, which serves as a guide for inserting the pilot
burner 22, is also formed in one piece with the inner burner tip
part 21 and the swirl vanes 32 in the present exemplary embodiment.
Exemplary embodiments without a tube 62 for guiding the pilot
burner 22 are also possible, however. The tube 62 which is shown in
the figure therefore represents only one option.
[0048] The structure of the pilot burner 22 in the region of the
burner tip 1 is shown in FIG. 4. The pilot burner tip part 31 and
the tubular section of the pilot burner 22 which is formed from the
three inter-inserted tubes 24, 26, 28 can be seen in the
figure.
[0049] The pilot burner tip part 31 has a wall 31A which is bent in
an approximately U-shaped manner and encloses an interior space of
the pilot burner tip part 31. A displacement body 25 is arranged in
the interior space. As in the case of the burner tip parts 11, 21
of the outer burner element 2 and of the inner burner element 12,
the displacement body 25 located in the interior space of the pilot
burner tip part 21 is also of hollow design. It has a near end 66
pointing towards the end side 76 and a far end 68 facing away from
this with a groove 25A of fitting onto the center tube 26 of the
tubular section of the burner element. Arranged in the region of
the far end 68, especially directly in front of the groove 25A in
the far end, is a displacement-body opening 70 via which the
interior space 72 of the displacement body 25 is accessible. The
displacement-body interior space 72 is enclosed by a wall 74 which
via support structures 76, for example the already described
pillar-like or rib-like structures, is connected to the inner side
of the burner-tip wall 31A. Also in the case of the burner-tip wall
of the pilot burner, the support structures 76 can be of a
flow-guiding design. In any case, however, they are designed so
that they do not obstruct the flow through the flow passage 30
which is formed between the outer side of the displacement body and
the inner side of the burner-tip wall 31A.
[0050] The two ends of the wall 31A--which is bent in an
approximately U-shaped manner--of the pilot burner tip part 31 are
connected to the outer tube 24 and to the inner tube 28 of the
tubular section of the pilot burner 22, and the displacement-body
wall 74 is connected to the center tube 26 of the tubular section.
The connection is constructed in this case at a point of the
displacement-body wall 74 which is selected in such a way that the
displacement-body opening 70 is open towards the feed passage which
is formed between the outer tube 24 of the tubular section of the
pilot burner 22 and its center tube 26. The displacement-body
interior space 72 is consequently integrated into the cooling fluid
circuit.
[0051] The outside diameter of the pilot burner 22 is selected so
that it can be inserted into the tube 62 of the inner burner
element 12. The pilot burner 22 also encloses a largely cylindrical
interior space in which an ignition burner and a flame monitoring
device can be arranged.
[0052] Both in the case of the outer burner element 2 and the inner
burner element 12 and in the case of the pilot burner 22, the
burner tip parts 11, 21, 31 are produced separately in each case
from the tubular sections which are formed by the inter-inserted
tubes. Subsequently, the inter-inserted tubes are then connected to
the respective burner tip parts by means of a welding process, for
example.
[0053] The burner tip parts can especially be produced in one piece
in each case by means of an additive manufacturing process. As a
result, the described complex structures, in which hollow
displacement bodies are connected to the burner-tip walls via
support structures, are made possible. In particular, the one-piece
production of the swirl vanes 32 and the tube 62 with the inner
burner tip part 21 can also be ensured by the additive production
by means of an additive manufacturing process 5. As an additive
manufacturing process, especially selective laser sintering can be
applied.
[0054] A modification of the exemplary embodiment shown in FIG. 3
is described below with reference to FIG. 5. The modification is
concentrated in the main upon the embodiment of the displacement
body and its interior space. The remaining elements of the
exemplary embodiment described in FIG. 3, such as the swirl vanes,
are therefore not shown in FIG. 5. Elements which correspond to
those from FIG. 3 are identified by the same designations as in
FIG. 3 and are not explained again in order to avoid
repetitions.
[0055] The displacement body of the exemplary embodiment shown in
FIG. 5 differs from the displacement body of the exemplary
embodiment shown in FIG. 3 mainly by the fact that its opening 50
is enlarged. Furthermore, a flow guiding element 80 projects from
the inner side for the inner burner wall into the displacement-body
opening 50 so that the flow guiding element 80 divides the opening
into an inflow section 81 and an outflow section 82.
[0056] A flow path 83 is formed around the flow guiding element 80.
At the end of the flow guiding element 80, the flow through the
flow path 83 experiences a flow reversal 84. In the region of the
flow reversal 84, a collecting chamber 85 branches from the flow
path 83, wherein the access to the collecting chamber is arranged
in approximately the original flow direction, that is to say the
flow direction before the flow reversal. Suspended particles
present in the cooling fluid are not able to reproduce the abrupt
direction change, on account of their inertia, during the flow
reversal as easily as the fluid itself so that the suspended
particles make their way into the collecting chamber 85 and can be
deposited there. In this way, some of the suspended particles can
be removed from the fluid before flow passes through the flow
passage 20 which is formed between the outer side of the
displacement body and the inner side of the burner-tip wall 21A, as
a result of which deposits of suspended particles in this flow
passage can be reduced so that a constriction of the flow passage
can be avoided or at least delayed.
[0057] Although the exemplary embodiment with the collecting
chamber 85 has been described with regard to the burner-tip part 21
of the inner burner element 12, a corresponding embodiment can also
be provided in the case of the burner tip part 11 of the outer
burner element 2 and also in the case of the pilot burner tip part
31.
[0058] A further alternative to the exemplary embodiment from FIG.
3 is shown in FIG. 6. Elements which correspond to those from FIG.
3 are identified in this case by the same designations as in FIG. 3
and are not explained again in order to avoid repetitions. As in
FIG. 5, in FIG. 6 the swirl vanes 32 and also the cylindrical tube
62 are not shown since these do not differ from the exemplary
embodiment shown in FIG. 3.
[0059] The essential difference to the exemplary embodiment shown
in FIG. 3 lies in the fact that the end wall 147 is of a thinner
design than in the case of the exemplary embodiment shown in FIG.
3. In order to stabilize the thin end wall 147, the density of
support structures 146 is increased in its region. The support
structures 146 are designed as pillar-like structures which
converge to form arches on the displacement body 15. In the present
exemplary embodiment, the arches are designed as pointed arches so
that the pillar-like support structures form a type of arch which
has the shape of a gothic arch.
[0060] Although in the exemplary embodiment shown in FIG. 6 only
the end wall 147 is of a thinner design, the thin wall can also
extend beyond the end wall 147 and even form the entire burner-tip
wall 21A. By reducing the thickness of the burner-tip wall 21A in
thermally highly loaded regions a more rapid heat dissipation to
the cooling fluid can be achieved. Furthermore, a thinner wall is
less prone to heat fluctuations.
[0061] The described pointed arch-like design of the support
structures can be realized by means of the already mentioned
additive manufacturing process. The design of the support
structures and of the wall thickness described with reference to
FIG. 6 can also be realized in the case of the burner tip parts 11,
31 of the outer burner element 2 and of the pilot burner 22.
[0062] An alternative form of the support structures, which also
enables a reduction of the wall thickness of the burner-tip wall,
is shown in FIGS. 7 and 8. In this case, FIG. 8 shows a section
along the line VIII-VIII shown in FIG. 7.
[0063] The support structures shown in FIGS. 7 and 8 have the form
of ribs 86 which are formed between the displacement-body wall 54
and the burner-tip wall 21A and extend from the far end of the
displacement body 15 around its near end and back towards the far
end. In this case, the ribs 86 extend in parallel and converge to
form arches both on the outer side of the displacement body and on
the inner side of the burner wall. In the present exemplary
embodiment, the arches are pointed arches so that between the
individual ribs flow passages 20 are formed with cross sections
which correspond to an ellipse running to a point at its ends. This
design of the support structures also allows a reduction of the
wall thickness with high stability of the thinner wall. The support
structures described with reference to the FIGS. 7 and 8 can be
used in the case of the burner tip part 11 of the outer burner
element 2 and/or the burner tip part 21 of the inner burner element
12 and/or the pilot burner tip part 31. Although pointed arches
have been described with reference to FIGS. 7 and 8, other arch
shapes can also be used, wherein the respective arch shape inter
alia can be selected with regard to the chosen production
method.
[0064] The present invention has been explained in detail based on
specific exemplary embodiments for illustration purposes. In this
case, elements of the individual exemplary embodiments can also be
combined with each other. The invention is therefore not to be
limited to individual exemplary embodiments but is only to
experience a limitation as a result of the appended claims.
* * * * *