Elliptical flanged finned tube

Abstract

The utility model relates to an oval flanged finned tube which can be used as a combustion head of a gas premixing combustor. The heat exchanger comprises fins and a base tube, the base tube is an oval tube, the fins are spirally and evenly wound on the outer wall of the base tube through flat steel strips, each fin comprises a fin root and a fin tip, and the fin roots and the outer wall of the base tube are welded through laser. The left side and the right side of the fin tip are pressed and formed through a die to form a left folded edge and a right folded edge, narrow gap channels are formed between the adjacent fins and the outer wall of the base tube after pressing and forming, the sections of the fins before pressing and forming are arranged to be of an oval annular structure, and overlapped parts exist between the adjacent fins after pressing and forming. After compression molding, all wing tips incline towards the same direction, the left and right folded edges and the outer wall of the base tube form a flaring structure, the left and right folded edges are parallel to the long axis of the ellipse, the upper and lower arcs on the two sides are symmetrically arranged, and the left and right folded edges on the two sides are symmetrically arranged.

Description

Technical Field

[0001] This utility model relates to an elliptical folded finned tube, which can be used as the burner head of a gas premixed burner. Background Technology

[0002] The burner head is a key component in a water-cooled premixed combustion burner, determining factors such as flame uniformity and safety. A circular, folded-edge finned tube is a representative structural form of this type of burner head, as seen in patent publication number CN210831977U. Figure 3 The image shows a circular finned tube with folded edges used as a burner head. Cooling water flows inside the tube, which can cool the temperature of the fins. It features strong anti-backfire capability, good anti-flameout performance, high safety and stability, high combustion efficiency, and low nitrogen oxide emissions.

[0003] However, as a burner head, the circular finned tube with folded edges has certain limitations in terms of combustion heat load per unit area, and the power of a single burner cannot be made very large. Utility Model Content

[0004] The purpose of this invention is to overcome the above-mentioned shortcomings in the existing technology and provide an elliptical finned tube with a reasonable structural design. The burner head made of this finned tube not only has the advantages of a circular finned tube, but also has stronger backfire prevention performance, a more compact structure, a larger combustion heat load per unit area, and the power of a single burner can be increased by more than 100%.

[0005] The technical solution adopted by this utility model to solve the above problems is as follows: the elliptical folded finned tube includes fins and a base tube. The base tube is an elliptical tube. The fins are made of flat steel strips spirally and evenly wound around the outer wall of the base tube. The fins include fin roots and fin tips. The fin roots are laser-welded to the outer wall of the base tube. Its structural feature is that the upper and lower sides of the fin tip are upper and lower arcs. The left and right sides of the fin tip are formed by mold pressing and forming left and right folded edges. After pressing and forming, a narrow gap channel is formed between adjacent fins and the outer wall of the base tube.

[0006] Furthermore, the cross-section of the pressed-molded front fin is set in an elliptical ring structure.

[0007] Furthermore, after pressing and molding, there is an overlap between adjacent fins.

[0008] Furthermore, after pressing and molding, all wing tips tilt in the same direction.

[0009] Furthermore, the left and right folds form a flared structure with the outer wall of the base tube.

[0010] Furthermore, the left and right folded edges are parallel to the major axis of the ellipse.

[0011] Furthermore, the upper and lower arcs on both sides are symmetrically arranged.

[0012] Furthermore, the left and right folded edges on both sides are symmetrically arranged.

[0013] Furthermore, the length of the narrow gap channel is equal to the length L of the left and right folded edges.

[0014] Furthermore, the fin pitch is p, with a value ranging from 1 to 4 mm; the fin thickness is t, with a value ranging from 0.2 to 1.5 mm; and the fin height is h, with a value ranging from 3 to 10 mm.

[0015] Compared with the prior art, this utility model has the following advantages:

[0016] 1. It has a narrow gap channel, the equivalent diameter of which is smaller than the quenching diameter of the flame, and the length of which is greater than the quenching length of the flame, and has an automatic backfire prevention function.

[0017] 2. The narrow gap channel is equal in length to the left and right folded edges. Compared with similar circular tube finned tubes, the narrow gap channel is longer and has better anti-backfire function.

[0018] 3. The left and right folds form a flared opening with the base pipe. When the flow rate of the mixed gas changes, the flame root moves in the flared direction to adapt to the change in flow rate. The flame root will not run out of the upper and lower arc lines to prevent flameout.

[0019] 4. The fin root and the base tube are laser welded, resulting in good fusion, low thermal resistance, and rapid heat transfer from the fins to the base tube, thus providing strong cooling capacity.

[0020] 5. Cooling water flows inside the base tube, which can absorb the heat transferred from the fins, making the fin temperature lower. During tempering, it can more quickly reduce the temperature of the flame in the channel and extinguish the flame. At the same time, under normal circumstances, it can also absorb some of the heat radiated by the flame to heat the cooling water inside the tube, reduce the flame temperature, and reduce the amount of nitrogen oxides generated.

[0021] 6. Under the same conditions, the burner power depends on the number of narrow gap channels. Since the minor axis of the elliptical tube is smaller than the diameter of the corresponding circular tube, the overall width W of the finned tube after folding is smaller than the overall width of the corresponding circular tube. Therefore, more elliptical folded finned tubes can be arranged within the same distance, that is, more narrow gap channels can be arranged. Thus, burners of the same size made with elliptical folded finned tubes can achieve greater power. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the main structure of the pressed and molded finned tube according to an embodiment of the present invention.

[0023] Figure 2 This is a top view of the pressed and molded finned tube according to an embodiment of the present invention.

[0024] Figure 3 yes Figure 1 A schematic diagram of the AA cross-sectional structure.

[0025] Figure 4 yes Figure 1 A schematic diagram of the BB cross-sectional structure.

[0026] Figure 5 yes Figure 4 A magnified schematic diagram of part I in the diagram.

[0027] Figure 6 This is a schematic diagram of the front finned tube of the present invention.

[0028] Figure 7 This is a left-side view of the pressed and molded front finned tube according to an embodiment of the present invention.

[0029] In the diagram: 1. Fin 2. Base tube 3. Narrow gap channel 3. Upper and lower arcs 11. Left and right folded edges 12. Fin root 13. Fin tip 14. Detailed Implementation

[0030] The present invention will be further described in detail below with reference to the accompanying drawings and through embodiments. The following embodiments are explanations of the present invention, but the present invention is not limited to the following embodiments.

[0031] Example

[0032] See Figures 1 to 7 As shown in the accompanying drawings, the structures, proportions, sizes, etc., depicted in this specification are merely for illustrative purposes to aid those skilled in the art and to provide a clear understanding. They are not intended to limit the scope of this invention and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, provided they do not affect the effectiveness or purpose of this invention, should still fall within the scope of the technical content disclosed in this invention. Furthermore, the use of terms such as "upper," "lower," "left," "right," "middle," and "one" in this specification is solely for clarity and not intended to limit the scope of this invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of this invention.

[0033] The elliptical finned tube in this embodiment includes fins 1 and a base tube 2. The base tube 2 is an elliptical tube, and its material is carbon steel, stainless steel or other materials, depending on the application. The fins 1 are made of flat steel strips spirally and evenly wound around the outer wall of the base tube 2. Before pressing, the fins 1 are approximately perpendicular to the outer wall of the base tube 2. Cooling water can flow through the base tube 2.

[0034] Fin 1 includes fin root 13 and fin tip 14. Fin root 13 is laser-welded to the outer wall of base tube 2 to form a single unit. After welding, fin tip 14 is pressed and formed using a mold. The left and right sides of fin tip 14 are pressed and formed into a set of left and right folded edges 12 that are parallel to the major axis of the ellipse and symmetrical (e.g., Figure 3 As shown), the length of the narrow gap channel 3 is equal to the length L of the left and right folded edges 12. The pitch of the fin 1 is p, and the value of p ranges from 1 to 4 mm. The thickness of the fin 1 is t, and the value of t ranges from 0.2 to 1.5 mm. The height of the fin 1 is h, and the value of h ranges from 3 to 10 mm. After pressing and forming, a narrow gap channel 3 is formed between the outer walls of adjacent fins 1 and base tube 2.

[0035] The cross-section of the pressed fin 1 is an elliptical ring structure, and the upper and lower sides of the fin tip 14 are upper and lower arcs 11 (e.g., Figure 7 As shown), after pressing and molding, there is an overlap between adjacent fins 1, and all fin tips 14 tilt in the same direction, and a narrow gap channel 3 is formed between adjacent fins 1 and the outer wall of the base tube 2 (as shown). Figure 5 As shown), the length of the narrow gap channel 3 is equal to the length L of the left and right folded edges 12. The left and right folded edges 12 form a flared structure with the outer wall of the base tube 2. The left and right folded edges 12 are parallel to the major axis of the ellipse. The upper and lower arcs 11 on both sides are symmetrically arranged, and the left and right folded edges 12 on both sides are symmetrically arranged.

[0036] Press-molded front fin 1 (e.g.) Figure 6 As shown), on the axial section of the finned tube, fin 1 is almost perpendicular to the base tube 2. Before pressing, the included angle α1 between fin 1 and base tube 2 is ≥85°, and fins 1 are parallel to each other and do not intersect. After pressing, fin 1 (as shown) Figure 5 As shown), all wing tips 14 on the pressed side are tilted in the same direction. The parts of adjacent wing 1 overlap each other except for a distance from the wing root 13. The angle between the overlapping wing 1 and the base tube 2 is the angle α2 between the pressed wing 1 and the base tube 2, where α2≤20°. An irregularly shaped narrow gap channel 3 is formed between the outer walls of adjacent wing 1 and base tube 2. The length of the narrow gap channel 3 is the length L of the straight side 12.

[0037] In order to have the function of automatically preventing backfire, the length of the narrow gap channel 3 should be greater than the quenching length of the corresponding gas flame, and the equivalent diameter of the narrow gap channel 3 should be smaller than the quenching diameter of the corresponding gas flame.

[0038] When used in a burner, the mixture of gas and air enters through a flared opening formed by the left and right folds 12 at one end and the corresponding outer surface of the base pipe 2, and then exits through a flared opening formed by the left and right folds 12 at the other end and the corresponding outer surface of the base pipe 2. It is then ignited and combustion begins. Since the cross-sectional area of ​​the flared opening is not fixed but gradually increases, when the combustion load increases, the flame root will move from the smaller part of the flared opening to the larger part of the flared opening. The flame root is always within the range of the flared opening, thus automatically preventing flame detachment.

[0039] When used in burners, water can flow through the base tube 2, resulting in better cooling, lower flame temperature, and less nitrogen oxide generation.

[0040] Wherein: the length of the left and right folded edges 12 is L, the pitch of the fin 1 is p, the thickness of the fin 1 is t, the height of the fin 1 is h, the included angle α1 between the fin 1 and the base tube 2 before pressing is formed, and the included angle α2 between the fin 1 and the base tube 2 after pressing is formed.

[0041] The length L of the left and right folded edges 12 is greater than the quenching length of the corresponding gas flame; the equivalent diameter of the narrow gap channel 3 is smaller than the quenching diameter of the corresponding gas flame; water can flow through the inside of the base tube 2, which makes the cooling effect better, the flame temperature lower, and the amount of nitrogen oxides generated less.

[0042] Furthermore, it should be noted that the specific embodiments described in this specification may differ in the shape and name of their components. The above description is merely illustrative of the structure of this utility model. All equivalent or simple variations made based on the structure, features, and principles described in this utility model patent concept are included within the protection scope of this utility model patent. Those skilled in the art to which this utility model pertains may make various modifications or additions to the described specific embodiments or use similar methods to replace them, as long as they do not deviate from the structure of this utility model or exceed the scope defined in these claims, all of which should fall within the protection scope of this utility model.

Claims

1. An elliptical finned tube, comprising a fin (1) and a base tube (2), the base tube (2) being an elliptical tube, the fin (1) being spirally and uniformly wound on the outer wall of the base tube (2) by a flat steel strip, the fin (1) comprising a fin root (13) and a fin tip (14), the fin root (13) being laser welded with the outer wall of the base tube (2), characterized in that: The upper and lower sides of the fin tip (14) are upper and lower arcs (11), the left and right sides of the fin tip (14) are formed by die pressing and are left and right folded edges (12), the left and right folded edges (12) are parallel to the long axis of the ellipse, and a narrow gap channel (3) is formed between the outer walls of adjacent fins (1) and base pipes (2) after die pressing. ​ 2. The elliptical fin-and-tube of claim 1, wherein: The cross section of the fin (1) before die pressing is in an elliptical ring structure.

3. The elliptical fin-and-tube of claim 1, wherein: There is an overlapping part between adjacent fins (1) after die pressing.

4. The elliptical fin-and-tube of claim 1, wherein: All fin tips (14) lean in the same direction after die pressing.

5. The elliptical fin-and-tube of claim 1, wherein: The left and right folded edges (12) form a flared structure with the outer wall of the base pipe (2).

6. The elliptical fin-and-tube of claim 1, wherein: The upper and lower arcs (11) on both sides are symmetrically arranged.

7. The elliptical fin-and-tube as claimed in claim 1, wherein: The left and right folded edges (12) on both sides are symmetrically arranged.

8. The elliptical fin-and-tube of claim 1, wherein: The length of the narrow gap channel (3) is equal to the length L of the left and right folded edges (12).

9. The elliptical fin-and-tube of claim 1, wherein: The pitch of the fin (1) is p, the value of p is in the range of 1-4 mm, the thickness of the fin (1) is t, the value of t is in the range of 0.2-1.5 mm, and the height of the fin (1) is h, the value of h is in the range of 3-10 mm.

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