Flame tube for improving temperature uniformity of radiant tube
By installing tubular flow bodies in the end area of the inner flame tube of the radiation tube in the industrial furnace, the problem of uneven temperature on the surface of the radiation tube is solved, and a more uniform temperature distribution and a more economical furnace design are achieved.
Patent Information
- Application Number
- CN202411220467.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-09-14
- Filing Date
- 2024-09-02
- Publication Date
- 2025-03-14
AI Technical Summary
In industrial furnaces, the temperature distribution of the radiation tube surface is uneven, resulting in the material that may oxidize or scale during the heat treatment process, and large areas of uneven temperatures require a larger furnace design, which increases cost and complexity.
The heating system of the radiation tube is optimized by installing at least one tubular flow body, such as a polygonal tubular body, in the end region of the inner flame tube opposite to the burner, to reduce undesired temperature rise.
A more uniform distribution of the surface temperature of the radiation tube is achieved, reducing the undesired temperature increase at the end of the radiation tube, and reducing the scale and cost of the furnace design.
Smart Images
Figure CN119617413A_ABST
Abstract
Description
Technical Field
[0001] Embodiments generally relate to industrial furnaces and radiant tubes used in such furnaces. Embodiments further relate to optimization of radiant tube heating systems. Background Art
[0002] Radiant heating tubes (often referred to as "radiant tubes") are used in industrial furnaces to ensure that the material within the heating chamber remains isolated from the exhaust gases generated during combustion or when special heat treatment conditions are required (such as forming a carburizing atmosphere). The exhaust gases typically contain residual oxygen, water vapor and / or CO2, and these elements can potentially cause oxidation of different materials.
[0003] For example, in order to avoid oxidation or scale formation of the material to be treated during heat treatment of metals, it may be necessary to prevent the products from coming into contact with the exhaust gases of the combustion. This can be achieved with radiant tubes, since the combustion takes place inside the radiant tubes close to the heating chamber and the exhaust gases from the combustion are not fed into the heating chamber. The interior of the radiant tubes thus represents the combustion chamber. The material to be treated and the radiant tubes used for heating can be arranged in the heating chamber.
[0004] High quality heat treatment requires a uniform temperature of the product. This means that the temperature of the radiant tube surface should be as uniform as possible and located at a sufficiently large distance from the material to the radiant tube. In case of non-uniform temperature distribution on the radiant tube surface, a larger distance between the material and the radiant tube may be required to compensate for this. A large distance requires a larger furnace design and therefore makes the furnace construction and the heat treatment more expensive. Summary of the invention
[0005] The following summary of the invention is provided to facilitate understanding of some features of the embodiments disclosed in the present invention, and is not intended to be a complete description. A comprehensive understanding of the various aspects of the embodiments disclosed herein can be obtained by taking the specification, claims, drawings and abstract as a whole.
[0006]
[0011] It is therefore an aspect of an embodiment to provide an improved radiant tube for use in an industrial furnace.
[0007] Another aspect of an embodiment is to provide a radiant tube in which an undesirable temperature increase is reduced.
[0008] Yet another aspect of the embodiments is to improve the temperature uniformity of the radiant tube surface of a fuel-heated radiant tube, in particular a single-sided closed shell radiant heating tube with an inner flame tube.
[0009] It is still another aspect of the embodiments to provide a method, apparatus, and system that can reduce the temperature rise at the radiant tube surface in the end region of the inner-fire tube opposite the burner in a radiant tube configuration.
[0010] The above aspects and other objectives can now be achieved as described herein.In an embodiment, a radiant tube arrangement can include a burner and an inner-fire tube and at least one flow body mounted in a region of the inner-fire tube at an end opposite the burner.
[0011] In embodiments of the radiant tube arrangement, at least one of the flow bodies may be tubular.
[0012] In one embodiment of the radiant tube arrangement, at least one flow body can protrude into the flame tube.
[0013] In an embodiment of the radiant tube arrangement, the at least one flow body can protrude into the flame tube by a length of, for example, approximately 0x to 1x the flame tube diameter.
[0014] In an embodiment of the radiant tube arrangement, the at least one flow body protrudes into the flame tube by a length of, for example, approximately 0.3x to 0.7x the diameter.
[0015] In an embodiment of the radiant tube arrangement, at least one flow body can be arranged in the region at an end of the radiant tube arrangement without overlapping.
[0016] In an embodiment of the radiant tube arrangement, at least one flow body may comprise a polygonal tubular body.
[0017] In an embodiment of the radiant tube arrangement, the at least one flow body may comprise an arrangement of a plurality of polygonal tubular bodies.
[0018] In embodiments of the radiant tube arrangement, each of the plurality of polygonal tubular bodies may be positioned adjacent to, behind, or inside each other.
[0019] In an embodiment of the radiant tube arrangement, the plurality of flow bodies for the displacement flow may include at least one flow body, such that a flow body of the plurality of flow bodies is individually or mostly or completely enclosed therein.
[0020] In an embodiment, the radiant tube arrangement may include a burner and an inner flame tube and at least one flow body mounted in a region of the inner flame tube at an end opposite the burner, wherein the at least one flow body is tubular and protrudes into the flame tube.
[0021] In an embodiment, a radiant tube heating system may include a plurality of interlocking tubes having different diameters and specific geometries, wherein the plurality of interlocking tubes are configured to mitigate undesirable temperature increases at radiant tube ends of the radiant tubes. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] The accompanying drawings, in which like reference numerals refer to identical or functionally similar elements throughout the individual views and are incorporated into and form a part of the specification, also illustrate embodiments and, together with the detailed description, serve to explain the principles of the embodiments.
[0023] Figure 1 An example of a configuration of a fuel-heated radiant heating tube having an outer radiant tube, a burner, and an inner flame tube is illustrated;
[0024] Figure 2 An exemplary and schematic temperature distribution of the surface of a fuel burning radiant tube is illustrated;
[0025] Figure 3 A schematic diagram illustrating a flow in an end region of an inner flame tube opposite to a burner in a radiant tube according to an embodiment;
[0026] Figure 4 A schematic diagram illustrating an example of flow in an end region of an inner flame tube in a radiant tube opposite to a burner having an additional mounting tube according to an embodiment;
[0027] Figure 5 A schematic diagram illustrating an example of a radiant tube according to an embodiment having three additionally installed interlocking tubes in the radiant tube; and
[0028] Figure 6 A schematic diagram of an exemplary radiant tube with additionally installed non-interlocking tubes in the radiant tube is illustrated in accordance with an embodiment.
[0029] The same or similar parts or elements in the drawings and the detailed description may be indicated by the same reference numerals. DETAILED DESCRIPTION
[0030] The specific values and configurations discussed in these non-limiting examples may vary, and are cited merely to illustrate one or more embodiments, and are not intended to limit the scope thereof.
[0031] The subject matter will now be described more fully below with reference to the accompanying drawings, which form a part of the subject matter and show specific exemplary embodiments by way of example. However, the subject matter can be embodied in a variety of different forms, and therefore the subject matter covered or claimed is intended to be construed as not limited to any exemplary embodiment listed herein; the exemplary embodiments are provided for illustration only. Likewise, the subject matter that is intended to be claimed or covered has a suitably broad scope. Among other things, the subject matter may be embodied as a method, device, component, or system. Thus, the embodiments may, for example, take the form of hardware, software, firmware, or a combination thereof. Therefore, the following specific embodiments are not intended to be construed as having a limiting meaning.
[0032] Throughout the specification and claims, in addition to the meanings explicitly stated, terms may have slightly different meanings suggested or implied by the context. Likewise, phrases such as "in an embodiment" or "in one embodiment" or "in an exemplary embodiment" and variations thereof as used herein may or may not necessarily refer to the same embodiment, and phrases "in another embodiment" or "in another exemplary embodiment" and variations thereof as used herein may or may not necessarily refer to different embodiments. For example, the claimed subject matter is intended to include, in whole or in part, a combination of the exemplary embodiments.
[0033] Generally speaking, the term can be understood at least in part from the usage in the context. For example, terms such as "and", "or" or "and / or" as used herein may include multiple meanings that may depend at least in part on the context in which such terms are used. Generally speaking, if "or" is used in an association list, such as A, B or C, it is intended to represent A, B and C used in an inclusive sense here, and A, B or C used in an exclusive sense here. In addition, the term "one or more" as used herein depends at least in part on the context and can be used to describe any feature, structure or characteristic in a singular sense, or can be used to describe a combination of features, structures or characteristics in a plural sense. Similarly, terms such as "one", "a kind of" or "the" also depend at least in part on the context and can be understood to convey singular usage or express plural usage. In addition, the term "at least one" can refer to "one or more". For example, "at least one widget" can refer to "one or more widgets".
[0034] Additionally, the term "based on" should be understood as not necessarily intended to convey an exclusive set of factors, but rather may depend, at least in part, on the context, allowing for the presence of additional factors that are not necessarily explicitly described again.
[0035] A radiant heating tube arrangement with a fuel-heated burner and a flame tube located inside the radiant heating tube often shows an undesirable temperature increase in the closed end region of the radiant tube. This temperature increase can be reduced by installing an additional tube or other flow bodies in the end region of the flame tube. This achieves a more uniform radiant tube surface temperature.
[0036] Figure 1 A side cross-sectional view depicting an example of a configuration of a fuel-heated radiant heating tube 10 having an outer radiant tube 20, a burner, and an inner flame tube is illustrated. Figure 1 The radiant tube heating system 10 shown in FIG. 1 may include one or more interlocking inner tubes such as, for example, inner tubes 13 , 15 , 12 , 14 . Figure 1 The configuration shown in comprises an inlet 16 for the cold air and an outlet 11 for the flue gases. Figure 1Also shown in FIG. 1 is an inlet 18 for gas to the left of the inlet 16 .
[0037] A non-limiting example of a radiant tube heating system that may be adapted for use in accordance with the embodiments is a self-regenerative burner such as Burners in which the combustion air is preheated by exhaust heat via a heat exchanger integrated in the burner and may involve indirect heating using single-ended radiant heating tubes. In such applications, the exhaust gas may generally pass through the heat exchanger of the burner. Since the exhaust gas heat is used to preheat the combustion air, the exhaust gas temperature drops and therefore the exhaust gas losses are reduced, which means that the combustion efficiency can be improved.
[0038] Figure 2 A diagram depicting an exemplary fuel-fired radiant tube 54 and an associated graph 50 of radiant tube temperature are illustrated in accordance with an embodiment. That is, Figure 2 An exemplary and schematic temperature profile 52 of the surface of a fuel burning radiant tube 54 is depicted (as shown in graph 50). This indicates that at least one object of the embodiments relates to reducing the temperature rise at the radiant tube surface in the region of the end 57 of the inner flame tube opposite the burner 56.
[0039] Please note that Figure 2 The fuel burning radiant tube 54 shown in is an example of a radiant tube that may be implemented according to an embodiment. However, it should be understood that variations in the configuration design of the fuel burning radiant tube 54 may be implemented according to alternative embodiments as shown and described herein (e.g., relative to Figures 3 to 6 ) to implement.
[0040] Figure 3 A side cross-sectional view of a radiant tube 21 is illustrated, which depicts the inner flame tube of the radiant tube 21 and the burner ( Figure 3 Flow in the region at the opposite end (not shown). Figure 3 The flow deflection in the tube can be concentrated in a narrow area. Such deflection and strong deflection in this area can increase the convective heat transfer of the external radiation tube. Figure 3 In FIG. 1 , dashed streamlines 22 illustrate the path of the flow.
[0041] The task of equalizing the temperature of the radiant tubes can be achieved by reducing the increased heat transfer in the end region of the flame tube by placing at least one additional tube or flowable body in the end region of the flame tube.
[0042] exist Figures 3 to 6, support feet 42 and 44 (e.g., 4×90° around the flame tube element) are depicted, which may be used in some embodiments to position the flame tube in the middle of the radiation tube. In addition, a bayonet-type connection 46 of the two flame tube elements may be implemented in some embodiments. It should be understood that the use of components such as support members 42 and 44 and / or bayonet-type connection 46 is optional and may not be required in an embodiment. As a reminder in the various figures depicted and discussed herein, the same or similar parts or elements.
[0043] exist Figure 4 In FIG. 1 , a side cross-sectional view of a radiant tube 31 is depicted, according to an embodiment, which has an optimized flow in the end region of the inner flame tube opposite the burner by means of an additional mounting tube 34 close to the end of the inner flame tube 33. Although the flow deflection is no longer concentrated, it is distributed over two sub-regions and in a wider area. As a result, the convective heat transfer is less enhanced in the nozzle end region and more distributed to the outer radiant tube. It should be noted that in Figure 4 In FIG. 1 , dashed streamlines 37 and 39 illustrate the paths of the flows.
[0044] In one embodiment, the additional tube 34 integrated into the inner flame tube can protrude into the flame tube; preferably with a length of, for example, 0x to 1x the flame tube diameter; preferably with a length of 0.5x the diameter. In another embodiment, the tube integrated into the inner flame tube can also be located in the end region of the flame tube without overlapping. Preferably subsequently, or at a small distance from the flame tube, with a length of 0x to 0.5x the diameter.
[0045] In the embodiment, an additional flow body with a desired geometry can also be installed instead of an additional tube to be installed in the flame tube. Such a flow body can be a circular or polygonal tubular body or an arrangement of several such flow bodies. In the embodiment, the arrangement of such flow bodies can be performed adjacent to each other, one after another or inside each other. In order to displace the flow, the flow body can be partially or completely closed inside to displace the flow. For example, the flow body can also be designed as a closed, circular or polygonal cylinder instead of a pipe. In this case, the exhaust gas does not flow through the flow body, but flows around the flow body.
[0046] Figure 4 The radiant tube shown in the figure may be cylindrical in shape and may include a plurality of inner tubes, including but not limited to inner tubes 33, 35, 34, etc. The additional inner tube 34 is Figure 4 34 is shown as being at least partially contained within the inner tube 33, wherein a portion of the inner tube 34 extends or protrudes outwardly from the inner tube 33. Note that Figure 4The radiant tube ends of the radiant tube shown in FIG. 3 may include at least inner tubes 35, 33, and 34. The radiant tube may include an outer tube 29 and one or more inner tubes such as tubes 33 and 35.
[0047] It should be understood that although Figure 4 Only tubes 33 and 35 are shown in the figure, but additional tubes may be included in the outer tube 29. The inner tubes 33 and 35 may be interlocked with each other by using a locking mechanism. The tubes 33 and 35 may have different diameters from each other. By interlocking the inner tubes 33 and 35 having different diameters and specific geometries, such as, for example, adding the inner tube 34, the undesirable temperature increase at the radiant tube end of the radiant tube 31 may be reduced. It should be noted that in some embodiments, the inner tubes 33, 34, 35, etc. may be used as flame tubes.
[0048] Figure 5 A schematic diagram illustrating an example of a radiant tube 51 according to an embodiment in which three interlocking tubes are additionally installed in the radiant tube 51. For example, although Figure 5 The radiation tube 51 shown in FIG. 5 includes Figure 3 and Figure 4 31 , but with the addition of the configuration of three interlocking tubes 34 , 64 , and 66 .
[0049] Figure 6 A schematic diagram of an exemplary radiant tube 61 according to an embodiment is illustrated, wherein there are additionally installed non-interlocking tubes in the radiant tube 61. Although Figure 6 The configuration depicted in includes Figure 5 The same features, but where at least some of the tubes 64 and 66 are in an arrangement where one or more of the tubes do not interlock.
[0050] For example, Figures 4 to 6 The tubular design shown in the embodiments of can solve the problems associated with heating industrial furnaces operated with conventional radiant tubes. This is a problem of high temperature uniformity of the tube surface required for a furnace that can be compact and cheap to construct and operate. These non-uniformities of surface temperature are caused by the geometry of traditional inner flame tubes, by the direction change of flue gas flow at the tube ends, by internal flue gas recirculation, and by very hot flames or by cooler mixing zones and thermal reaction zones in the case of flameless combustion. The embodiments discussed herein can solve these problems in the following manner: by using interlocking tubes with different diameters and specific geometries to optimize the radiant tube heating system, so as to reduce the undesirable temperature rise at the radiant tube ends, as discussed herein.
[0051] Note that as used herein and in the context of improving the uniformity of radiant tube temperature in a radiant tube heating system, the term "uniformity" may relate to the degree of consistency or even distribution of temperature along the length of the radiant tube. The term "uniformity" may mean the absence of significant temperature variations or hot / cold spots within the tube.
[0052] In radiant tube heating systems, uniformity is critical to ensuring efficient and effective heat transfer to the surrounding space. When the temperature is uniform, it means that the radiant heat emitted by the tube is evenly distributed, thereby providing consistent and comfortable heating throughout the desired area. Achieving uniformity in radiant tube temperature can involve minimizing temperature gradients or variations along the length of the tube. This can be achieved through careful design considerations such as those disclosed herein, including proper sizing and positioning of the radiant tubes, effective burner controls, and regular maintenance of the system. By improving uniformity, radiant tube heating systems can provide a more consistent and balanced heat distribution, thereby enhancing comfort and energy efficiency.
[0053] Furthermore, as used herein and in the context of optimizing a system to reduce an undesirable temperature rise at the ends of a radiant tube by using interlocking tubes with different diameters and specific geometries, the term "optimized" and related terms such as "optimize" and "optimized" and variations thereof, relate to a state or condition in which a radiant tube heating system has been improved or adjusted to achieve the best possible performance, efficiency, or desired result. The term optimization may relate to making changes or implementing strategies that maximize the benefits or advantages of a system while minimizing any disadvantages or inefficiencies. The term "optimization" may represent an effective process of modifying, adjusting, or improving a radiant tube heating system to enhance its performance, efficiency, or functionality. Optimization may involve analyzing an existing system, identifying areas for improvement, and implementing changes to achieve a desired goal. The term "optimized" may describe a radiant tube heating system that has undergone an optimization process and has been adjusted or designed to operate at its highest level of efficiency or effectiveness. An optimized system may be described as a system that has been fine-tuned to minimize inefficiencies, improve performance, and achieve a desired result such as, in this case, reducing the temperature rise at the ends of the radiant tubes.
[0054] Optimizing a radiant tube heating system in the context of interlocking tubes of varying diameters and specific geometries can involve carefully designing - also utilizing fluid flow and thermal calculations (CFD), for example - the tube configuration to promote more balanced heat distribution, reduce temperature variations, and mitigate undesirable temperature rise at the tube ends. The goal is to find an optimized arrangement of interlocking tubes that effectively distributes heat evenly and efficiently throughout the system, resulting in improved overall performance and enhanced thermal comfort.
[0055] Based on the foregoing, it can be appreciated that various embodiments are disclosed herein. For example, in an embodiment, a radiant tube arrangement may include a burner and an inner flame tube and at least one flow body that may be mounted in a region at an end of the inner flame tube opposite the burner.
[0056] In an embodiment, at least one flow body may be tubular in shape.
[0057] In embodiments, at least one flow body may protrude into the flame tube.
[0058] In embodiments, the at least one flow body may protrude into the flame tube with a length of approximately 0x to 1x the flame tube diameter.
[0059] In embodiments, the at least one flow body may protrude into the flame tube by a length of approximately 0.3x to 0.7x the diameter.
[0060] In embodiments, at least one flow body can be arranged in the region at the end without overlapping.
[0061] In an embodiment, at least one flow body may include a polygonal tubular body.
[0062] In an embodiment, at least one flow body may comprise an arrangement of a plurality of polygonal tubular bodies.
[0063] In an embodiment, each of the plurality of polygonal tubular bodies may be positioned adjacent to, behind, or inside each other.
[0064] In embodiments, a plurality of flow bodies may be provided for displacement flow, including at least one flow body, wherein the flow bodies of the plurality of flow bodies may be individually or mostly or completely enclosed therein.
[0065] In an embodiment, the radiant tube arrangement may include a burner and an inner flame tube and at least one flow body mounted in a region of the inner flame tube at an end opposite the burner, wherein the at least one flow body is tubular and protrudes into the flame tube.
[0066] In an embodiment, the radiant tube device may include a burner and an inner flame tube; and at least one flow body installed in a region at an end of the inner flame tube opposite to the burner, wherein the at least one flow body is tubular and protrudes into the flame tube, wherein the at least one flow body is arranged in the region at the end without overlapping.
[0067] It will be appreciated that the variations disclosed above and other features and functions or their alternatives may be advantageously combined into many other different systems or applications. It will also be appreciated that various currently unforeseen or unanticipated alternatives, modifications, variations or improvements may be subsequently made by those skilled in the art, which are also intended to be covered by the following claims.
Claims
1. A radiant tube device, comprising: Burners and inner flame tubes; as well as At least one flow body is mounted in the region of the inner-flame tube at the end opposite the burner.
2. The radiant tube arrangement of claim 1, wherein the at least one flow body is tubular.
3. The radiant tube arrangement of claim 1, wherein the at least one flow body protrudes into the flame tube. 4 . The radiant tube arrangement of claim 1 , wherein the at least one flow body protrudes into the flame tube with a length of approximately 0× to 1× the diameter of the flame tube.
5. The radiant tube arrangement of claim 1, wherein the at least one flow body protrudes into the flame tube by a length of approximately 0.3x to 0.7x the diameter. 6 . The radiant tube arrangement as claimed in claim 1 , wherein the at least one flow body is arranged in the region at the end without overlapping.
7. The radiant tube arrangement of claim 1, wherein the at least one flow body comprises a polygonal tubular body.
8. A radiant tube device, comprising: Burners and inner flame tubes; as well as At least one flow body is mounted in the region of the inner flame tube at the end opposite the burner, wherein the at least one flow body is tubular and protrudes into the flame tube. 9 . The radiant tube arrangement as claimed in claim 8 , wherein the at least one flow body is arranged in the region at the end without overlapping.
10. A radiant tube device, comprising: Burners and inner flame tubes; as well as At least one flow body is mounted in the region of the inner flame tube at the end opposite the burner, wherein the at least one flow body is tubular and protrudes into the flame tube, wherein the at least one flow body is arranged in the region of the end without overlapping.