阅读说明：本技术 燃烧器 (Burner with a burner head ) 是由 J·特卡特 于 2018-07-19 设计创作，主要内容包括：本发明涉及一种燃烧器(1),所述燃烧器具有壳体(2),在所述壳体上设置燃烧管(3),所述燃烧管(3)在背向壳体(2)的端部上具有开口(4),在所述燃烧管(3)中设有混合元件(5),并且在所述混合元件(5)与所述开口(4)之间的空间形成燃烧室(6),壳体(2)具有至少两个彼此分开的通道(8),这些通道在混合元件(5)中引出,气体流动通过所述通道(8)和混合元件(5)并且在燃烧室(6)中才进行所述气体的混合,其中,所述混合元件(5)是通过增材式制造方法制造的并且具有至少两个分开的中间通道(9),所述中间通道朝燃烧室(6)的方向上沿流动通过方向分支。(The invention relates to a burner (1) having a housing (2), a combustion tube (3) is arranged on the housing, the combustion tube (3) having an opening (4) at the end facing away from the housing (2), a mixing element (5) is arranged in the combustion tube (3) and a combustion chamber (6) is formed in the space between the mixing element (5) and the opening (4), the housing (2) having at least two channels (8) separated from each other, these channels lead out in a mixing element (5), the gases flow through the channels (8) and the mixing element (5) and are mixed only in the combustion chamber (6), wherein the mixing element (5) is manufactured by an additive manufacturing method and has at least two separate intermediate channels (9), the intermediate channel branches in the direction of flow through in the direction of the combustion chamber (6).)

1. Burner (1) having a housing (2) on which a combustion tube (3) is arranged, the combustion tube (3) having an opening (4) at the end facing away from the housing (2), a mixing element (5) being arranged in the combustion tube (3), and a combustion chamber (6) being formed in the space between the mixing element (5) and the opening (4), the housing (2) having at least two mutually separate channels (8) which lead out in the mixing element (5), the gases flowing through the channels (8) and the mixing element (5) and the mixing of the gases taking place only in the combustion chamber (6),

it is characterized in that the preparation method is characterized in that,

the mixing element (5) is produced by an additive manufacturing method and has at least two separate intermediate channels (9) which branch off in the flow-through direction in the direction of the combustion chamber (6).

2. Burner (1) according to claim 1, characterized in that the mixing element (5) is constructed in one piece.

3. Burner (1) according to claim 1 or 2, characterized in that three to five intermediate channels (9) are provided.

4. Burner (1) according to one or more of claims 1 to 3, characterized by the fact that said intermediate channel leads out in a plurality of outlets (10), for at least one intermediate channel the outlet cross section (11) being reduced with respect to the channel cross section (12).

5. Burner (1) according to one or more of claims 1 to 4, characterized by the fact that each single outlet (10) is equipped with mixing, swirling and/or atomizing elements for the gases when they flow out from the mixing element (5).

6. Burner (1) according to one or more of claims 1 to 5, characterized by swirl elements, baffle elements, flow separation edges, blocking edges, slots, mixing nozzles, mixing valves and/or exhaust elbows at the outlet (10).

7. Burner (1) according to one or more of the claims from 1 to 6, characterized by the fact that at least one of said intermediate channels (9) has a helical groove.

8. Burner (1) according to one or more of claims 1 to 7, characterized by the fact that said outlets (10) are arranged so that a homogeneous mixing of the gases is achieved in the combustion chamber (6) through a plurality of outlets (10) reduced with respect to the outlet cross section (11) of the channel cross section (12) with the separately manipulable intermediate channels (9).

9. Burner (1) according to one or more of claims 1 to 8, characterized by a UV or IR flame sensor (13) at the outlet side of the mixing element (5).

10. Burner (1) according to one or more of claims 1 to 9, characterized by the fact that the exhaust gases coming from the combustion chamber (6) can be caused to flow back in the direction of the casing (2) by means of one or more of said intermediate channels (9).

11. Burner (1) according to one or more of claims 1 to 10, characterized by the fact that the recirculated exhaust gases release heat through the walls of the intermediate channel (9) towards the gases flowing in the direction of the combustion chamber (6).

Technical Field

The invention relates to a burner with a housing, on which a burner tube is arranged, which has an opening at the end facing away from the housing, in which burner tube a mixing element is arranged, and in which space between the mixing element and the opening a combustion chamber is formed, the housing having at least two channels which are separate from one another and which lead out in the mixing element, through which channels and the mixing element the gases flow and only mix them in the combustion chamber.

Background

Such burners, in particular gas burners for industrial use, are devices which convert chemical energy into thermal energy during the combustion process. In the combustion process, at least one oxidizing agent, preferably air or oxygen, is combusted in a combustion chamber with the release of heat in a continuous reaction together with a fuel. The heated exhaust gases are released through the openings into the open environment and can be used, for example, in drying plants, thermal after-combustion devices, circulation systems, curing ovens or other process-technical plants. As fuel, for example, all commercially available purified gases, such as city gas, remote gas, natural gas and liquefied gas and mixtures thereof with air, can be burned.

Burners known from the prior art can be divided into two categories, wherein burners in which an oxidant and a fuel are injected into the combustion chamber as a mixture belong to the first category. Such burners are also referred to as premix burners. In contrast to burners of the first type, burners belonging to the second type have separate feed lines for the oxidant and the fuel to the combustion chamber, so that the mixing of the two substances takes place only in the combustion chamber.

The first type of burner, although having the advantage of providing a mixture of oxidant and fuel in a homogeneous state in the combustion chamber, also has the disadvantage of not having absolute safety against flashback. In the case of the second type of burner, flashback is avoided by supplying oxidant and fuel separately, but the homogeneity of the mixture in the combustion chamber is not optimal compared to that achieved with the mixture of the first type of burner.

Additive manufacturing methods for manufacturing burner elements are known from US 2016/0377293 a1, US 2016/0223201a1 and from GB 2536965A, since this applies in particular to complex structural parts.

Disclosure of Invention

The present invention relates to a burner of the second type and, in view of the above-mentioned conflict between safety and achieving optimum combustion through a high homogeneity of the mixture, proposes the object of providing a burner of the second type which achieves an improved homogeneity of the mixture in the combustion chamber in order to optimize the combustion process.

According to the invention, this object is achieved in a burner of the type mentioned in the introduction by the features of claim 1.

Thus a burner is provided in which the mixing element is produced by an additive manufacturing method. Additive manufacturing processes also include primarily powder bed processes, especially selective laser melting and selective laser sintering. By manufacturing the mixing element in an additive manufacturing method, a new way of supplying oxidant and fuel into the combustion chamber can be achieved, which supply can be optimized in such a way that a homogeneous mixing can be achieved over a wide adjustment range by the ratio of oxidant to fuel, and thereby ensuring that complete combustion is achieved over the entire performance range of the burner.

The mixing element has at least two separate intermediate channels which branch off in the flow direction in the direction of the combustion chamber. Although a branched and then led-out intermediate channel has been disclosed by US 2016/0223201a1, this document does not relate to a gas burner, but rather to a fuel injector for a gas turbine engine. This is a fuel injector similar to the first type of gas burner, where oxidant is injected as a mixture into the combustion chamber together with fuel (so-called premix burner).

The present invention relates to a second type of burner in which the separate delivery of oxidant and fuel to the combustion chamber is achieved by two passages. However, US 2016/0223201a1 has only one main supply channel, as can be seen clearly from fig. 2. A node is provided on the main supply channel, from which two (not separate) branching lines branch off in the turbine.

One problem that should not be underestimated in the operation of the burner is the formation of harmful nitrogen oxides that may occur during the combustion process. Here, the design of the burner, in particular of the combustion chamber, and the supply of oxidant and fuel have a great influence on the formation of nitrogen oxides during the combustion process. The additively manufactured mixing element can be optimized in such a way that the formation of such nitrogen oxides is completely suppressed or minimized. In this case, it is conceivable that the burner is provided with an exhaust gas recirculation device in which the already burnt exhaust gas with a low oxygen content and a higher carbon dioxide content is introduced into the combustion chamber. The injection of such inert exhaust gases leads to a significant reduction in the formation of nitrogen oxides.

Furthermore, it is also conceivable to design the burner and/or the mixing element such that the exhaust gas recirculation is arranged before the heating of the oxidizing agent and/or the fuel supplied into the combustion chamber.

Further embodiments of the invention emerge from the dependent claims.

Here, the mixing element is expediently formed in one piece. The advantage of an integrated mixing element is that the supply of oxidant and fuel into the combustion chamber is possible while the mixing element has a compact size. Furthermore, the supply of oxidant and fuel may be configured in ways and forms that are not achievable with multi-piece mixing elements. At the same time, the invention provides that the mixing element has at least two separate intermediate channels which branch off in the flow direction in the direction of the combustion chamber. This branching of the intermediate channel ensures that the oxidizing agent and/or the fuel is injected not only locally at one point into the combustion chamber, but at a plurality of possible points, so that a substantially homogeneous mixing of the oxidizing agent and the fuel is already achieved in the initial region of the combustion chamber. The initial region of the combustion chamber is to be regarded here as a region which has a smaller distance to the mixer than to the burner opening. The homogeneous mixing of the oxidant and fuel not only inhibits the formation of nitrogen oxides, but also increases the efficiency of the combustor and thereby reduces fuel costs.

Furthermore, it is preferably provided that three to five intermediate channels are provided. This choice is an optimum between the structural expenditure of the mixing element and its manufacturing requirements and the advantages to be achieved in terms of optimum combustion.

In a further embodiment, it is provided that the intermediate channel leads out in a plurality of outlets, the outlet cross section being reduced relative to the channel cross section for at least one intermediate channel. The reduction in the outlet cross section offers the advantage that a plurality of outlets can be provided on the side of the mixing element facing the combustion chamber, which outlets allow an optimum mixing of the oxidant and the fuel. On the other hand, it is therefore also possible to supply a large gas volume flow to the mixing element, since the passage to the mixing element has a large diameter.

It is furthermore provided that each individual outlet is equipped with suitable mixing, swirling and/or atomizing elements for the gas leaving the mixing element. By means of these elements, the gas is swirled turbulently on exit, so that the oxidizing agent can be mixed particularly homogeneously with the fuel. The advantage here is that homogeneity of the mixing of the oxidant and the fuel is already achieved when entering the initial region of the combustion chamber.

In a further embodiment, provision is made for swirl elements, baffle elements, flow separation edges, blocking edges, slots, mixing nozzles, mixing valves and/or exhaust gas elbows to be provided at the outlet. This is not to be understood as meaning that all outlets have the same element, but that one of the aforementioned elements is provided depending on the position of the outlet, which element results in an improved homogeneity of the mixture as a whole. This makes it possible to realize a plurality of combinations of different elements, so that the mixing elements can be adapted to the requirements of a determined burner class.

A special embodiment of the invention provides that at least one of the intermediate ducts has a spiral-shaped groove. In this case, the respective groove can have a rectangular cross section, for example, or can also be of diamond-shaped design. By introducing the spiral groove into the intermediate channel, the entry velocity of the respective gas into the combustion chamber can be controlled so as to achieve a high degree of homogeneity of the mixing of the oxidant and the fuel.

In a further special embodiment of the invention, the outlet is arranged such that a homogeneous mixing of the gases in the combustion chamber is achieved. Thereby increasing the efficiency of the burner and at the same time suppressing the formation of harmful nitrogen oxides. The supply of the oxidant and the fuel can take place via a plurality of channels, wherein, depending on the power range, a single supply structure is closed or opened, for example, in the region of the burner housing. Complete combustion can thereby be achieved over the entire power range of the burner.

It is also preferably provided that a UV or IR flame sensor is arranged on the outlet side of the mixing element. The combustion process can thus be continuously monitored in order to adapt the supply of oxidant and/or fuel, if necessary, in such a way that the combustion process is carried out according to the desired criteria. For this purpose, the flame sensor can be connected in terms of information technology to a suitable control or regulating unit, which can be arranged, for example, in the housing of the burner.

In addition, it is provided that the exhaust gases from the combustion chamber can flow back in the direction of the housing via one or more intermediate ducts. The recirculated exhaust gas can preheat the gas flowing in the direction of the combustion chamber, in particular, via the wall of the intermediate duct. Since the cool combustion air now flows around the hot exhaust gas-conducting channel, it is preheated. This increases the efficiency of the burner in the form of a heat exchanger-burner, where the particular advantages of a heat exchanger manufactured by 3D printing are exploited. Thereby, a very compact heat exchanger is obtained inside the mixing unit with good efficiency.

Drawings

Further features, details and advantages of the invention emerge from the following description and with reference to the drawings. Objects or elements that correspond to each other are provided with the same reference numerals throughout the figures. Wherein

Figure 1 is a schematic view of a burner according to the invention,

figure 2 is a perspective view of a mixing element configured as a two-channel system according to the invention,

figure 3 is a phantom exploded view of the mixing element of figure 2,

figure 4 is a view of the inlet side of the mixing element of figure 2,

figure 5 is a view of the outlet side of the mixing element of figure 2,

figure 6 is a cross-sectional view of the mixing element of figure 2 taken along line a-a,

figure 7 is a perspective view of a mixing element configured as a three-channel system according to the present invention,

figure 8 is a phantom exploded view of the mixing element of figure 7,

figure 9 is a view of the inlet side of the mixing element of figure 7,

figure 10 is a view of the outlet side of the mixing element of figure 7,

figure 11 is a perspective view of a mixing element configured as a four-channel system according to the present invention,

figure 12 is a phantom exploded view of the mixing element of figure 11,

figure 13 is a view of the inlet side of the mixing element of figure 11,

figure 14 is a view of the outlet side of the mixing element of figure 11,

figure 15 is a perspective view of a mixing element according to the invention,

FIG. 16 is a variation of FIG. 15, with schematic gas arrows, an

Fig. 17 is a view of the inlet side of a mixing element with a recirculator.

Detailed Description

Fig. 1 shows a schematic view of a burner according to the invention, comprising a housing 2, on which a burner tube 3 is arranged, which burner tube 3 has an opening 4 at the end facing away from the housing 2. A mixing element 5 is provided in the burner tube 3 and the space between said mixing element 5 and the opening 4 forms a combustion chamber 6. In this embodiment, the first passage 8 extends at least partially through the housing 2 and the burner tube 3. The spatial volume or intermediate chamber 7 between the burner tube 3 and the first channel 8 forms a further channel.

The housing 2 therefore has at least two channels 8 which are separate from one another and which lead out in the mixing element 5, wherein the gases are conveyed or flow through the channels 8 and the mixing element 5 and the mixing of these gases only takes place in the combustion chamber 6. For the sake of clarity, the connection between the housing 2 and the channel formed by the intermediate chamber 7 is not shown. In the combustion chamber 6, a UV or IR flame sensor is provided on the outlet side of the mixing element 5 in order to continuously monitor the combustion process. The ignition device igniting the gas mixture in the combustion chamber 6 is not shown.

The mixing element 5 configured as a two-channel system is shown in perspective view in fig. 2, in phantom exploded view in fig. 3, on the inlet side in fig. 4, on the outlet side in fig. 5, and as a sectional view in fig. 6. The exploded view in fig. 3 is supposed to be used for an overview only, and in reality the individual components of the mixing element 5 cannot be separated, since this would lead to a destruction of the mixing element 5, since the mixing element 5 is integrally formed by an additive manufacturing method. The inlet side refers to the side of the mixing element 5 which adjoins the intermediate chamber 7 in the installed state in the burner 1. The outlet side refers to the side of the mixing element 5 which adjoins the combustion chamber 6 in the installed state in the burner 1.

The mixing element 5 preferably has a tubular outer wall 14 provided with flow resistance elements 16 projecting radially inwards, which flow resistance elements 16 are preferably oriented transversely to the longitudinal axis of symmetry or axis of rotation of the outer wall 14. The flow resistance elements 16 may be separated in the radial direction by tube segments having a smaller diameter and a shorter longitudinal length than the outer wall 14. The flow resistance elements 16 can thus be arranged transversely to the longitudinal axis of symmetry of the outer wall 14 at different angles depending on their radial position. The flow resistance elements 16 may preferably be constructed in the form of impellers.

Preferably an inner or first channel 8 through which the gaseous fuel is conducted, said first channel branching into a plurality of intermediate channels 9 which pass through the flow resistance element 16 and the associated pipe section. The intermediate channel 9 has an outlet 10 which opens into the combustion chamber 6. For the sake of clarity, possible swirl elements, baffle elements, flow separation edges, blocking edges, slots, mixing nozzles, mixing valves and/or exhaust elbows on the opening 10 are not shown. The second channel 8 or intermediate chamber 7 for the oxidizing agent is formed by the space delimited by the outer wall 14 and the channel 8 and its intermediate channel 9. This embodiment is advantageous in that the intermediate channel 9 itself constitutes an additional flow resistance element. The intermediate channel 9 therefore not only has the function of delivering fuel into the combustion chamber, but also contributes to the swirling of the oxidant. In this embodiment, the channel cross-section 12 of the first channel 8 is chosen to be larger than the cross-section of the outlet 10 in order to achieve an even distribution of the fuel.

Fig. 7 shows a perspective view, fig. 8 shows an exploded view in phantom, fig. 9 shows a further mixing element 5 on the inlet side, fig. 10 shows the outlet side, which is designed as a three-channel system. The exploded view in fig. 8 is assumed for the sake of overview only, and in reality the different components of the mixing element 5 cannot be separated.

In contrast to the two-channel system, the three-channel system has an additional channel 8, which is arranged, for example, in the first channel 8. This additional channel 8 also has its associated intermediate channels 9, which extend through the flow resistance element 16 and its associated tube section. This additional channel 8 can be used, for example, to inject additional fuel into the combustion chamber 6 and thus to optimize the combustion process.

Fig. 11 shows a perspective view, fig. 12 shows an exploded view in phantom, fig. 13 shows a special mixing element 5 in the form of a four-channel system on the inlet side, fig. 14 shows the outlet side. The phantom exploded view in fig. 12 is only for an overview and in reality the different components of the mixing element 5 cannot be separated.

Unlike the three-channel system, this four-channel system has a tubular intermediate wall 15 which has a smaller diameter than the outer wall 14 but has substantially the same longitudinal extension.

As is shown in particular in fig. 15 and 16, the combustion air can flow into the combustion chamber 6 via the inner channel 8 and can flow out again via one of the outer channels 8. In order to change the flow direction and to re-supply the combustion air with the inwardly flowing exhaust gases, a recirculator 17 is provided (fig. 17).

Of course, the invention is not limited to the embodiments shown. Other designs may also be employed without departing from the basic concept. Of course, the supply of oxidant and fuel for a burner with a mixing element configured as a three-channel system or a four-channel system must be adapted accordingly. Furthermore, the number of channels is not limited to the above exemplary illustrated embodiment. Depending on the presetting and the field of application of the burner, it may also be advisable to provide more passages.

List of reference numerals

1 burner

2 casing

3 burner tube

4 opening

5 mixing element

6 combustion chamber

7 middle chamber

8 channel

9 middle channel

10 outlet port

11 outlet cross section

12 channel cross section

13 UV or IR flame sensor

14 outer wall

15 intermediate wall

16 flow resistance element

17 recirculator