Two-in-one return elbow

Abstract

The present invention provides a two-in-one return elbow, which is an integrated structure, and has an ∈-shaped flow channel with openings in the same direction inside, the ∈-shaped flow channel is respectively connected with two inlet interfaces and one outlet interface, the two inlet interfaces are arranged adjacent to each other, and are arranged in the same direction as the outlet interfaces. The two-in-one return elbow of the present invention does not occupy too much height space, thereby effectively extending the straight tube length of the two first-pass tubes, increasing the specific surface area, and effectively reducing the number of components and the number of welds, thereby reducing the risk of weld cracking.

Description

Technical Field

[0001] The invention relates to the field of petrochemical industry, and in particular to a two-in-one return elbow used in a tubular furnace in petrochemical production. Background Art

[0002] Most of the two-in-one pipe fittings used to connect furnace tubes in various tubular furnaces are of "Y" type structure.

[0003] There are also "Y-type two-in-one pipe fittings" in some tubular furnaces, which are used for the inlet or outlet of multi-pass coils.

[0004] The two-pass-in-one return coil with a "Y"-shaped structure is connected with a "Y-shaped two-in-one pipe fitting" (+ straight pipe) + 180° return elbow to achieve a 180° return.

[0005] This connection method of "Y-type two-in-one pipe fitting (+ straight pipe) + 180° return elbow" shortens the length of the double pipes in a limited space if a straight pipe structure is used, affecting the heat transfer effect; if a combination of "Y-type two-in-one pipe fitting" and 180° return elbow is used, the two pipe fittings with relatively large rigidity are welded, which brings a higher risk of weld cracking and has a relatively large restraining force on the furnace tube, which can easily cause the furnace tube to deform. Summary of the invention

[0006] The purpose of the present invention is to solve the problems existing in the above-mentioned prior art and provide a two-in-one return elbow, which can shorten the length and reduce the risk of weld cracking.

[0007] To achieve the above object, the technical solution adopted by the present invention is:

[0008] A two-in-one return elbow, characterized in that it is an integrated structure with an ∈-shaped flow channel with openings in the same direction inside, the ∈-shaped flow channel is interconnected with two inlet interfaces and one outlet interface respectively, the two inlet interfaces are arranged adjacent to each other and are arranged in the same direction as the outlet interface.

[0009] The two-in-one return elbow, wherein: the central axes of the two inlet interfaces and the outlet interface are located on the same plane.

[0010] The two-in-one return elbow, wherein: the two-in-one return elbow is made by casting, or manufactured by machining or 3D printing.

[0011] The two-in-one return elbow, wherein: a conical boss is integrally extended from the bottom of the two-in-one return elbow, and the conical boss is used for welding the guide rod.

[0012] The two-in-one return elbow, wherein: the inlet interface close to the outlet interface has a thickened convex corner extending inwardly on the inner wall adjacent to the other inlet interface.

[0013] The two-in-one return elbow, wherein: the wall surface of the outlet interface gradually becomes thicker from the outlet interface inward.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] 1. The two-in-one return elbow adopts a casting process, so that two inlets, one outlet and a guide connection boss are integrally cast at one time, and the two-in-one conversion of the furnace tube is optimized from multiple parts to a single part, reducing welds and risks; at the same time, it reduces the occupied height space, effectively extends the straight tube length of the two first-pass tubes, and increases the specific surface area.

[0016] 2. The two-in-one return elbow has two inlets and one outlet, and the middle cavity design structure fully considers the influence of the flow velocity of the fluid in the cavity that may produce eddy currents, etc., and reduces the eddy currents and recirculation areas from the structural point of view, reducing the resistance drop. At the same time, considering the impact of the fluid on the erosion and abrasion of the components, the structural dimensions are optimized, the wall thickness is increased, etc., to reduce the erosion and increase the service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a cross-sectional view of the two-in-one return elbow of the present invention.

[0018] Figure 2 for Figure 1 Top view of the .

[0019] Figure 3 , Figure 4 , Figure 5 They are Figure 1 AA, BB, and CC cross-sectional views.

[0020] Figure 6 It is a three-dimensional appearance diagram of the two-in-one return elbow of the present invention.

[0021] Figure 7 It is a schematic diagram of the present invention applied to a radiation coil. DETAILED DESCRIPTION

[0022] The present invention is further described in detail below in conjunction with the accompanying drawings.

[0023] In order to overcome the shortcomings of the "'Y-type two-in-one pipe fitting' (+ straight pipe) + 180° return elbow" type two-in-one furnace tube structure and retain the existing advantages, the present invention uses a two-in-one return elbow pipe fitting to connect two furnace tubes with one furnace tube, optimize the furnace tube structure and fluid flow pattern, and improve the tube group stress.

[0024] like Figure 1-Figure 6As shown, the present invention provides a two-in-one return elbow, which is an integrated structure and can be manufactured by casting or by other methods such as machining and 3D printing. Its main feature is that it has two inlet interfaces 1 and one outlet interface 2, the two inlet interfaces 1 are arranged adjacent to each other, and are both arranged upward with the outlet interface 2, the central axes of the two inlet interfaces 1 and the outlet interface 2 are located on the same plane, and the interior of the two-in-one return elbow has an ∈-shaped flow channel with the same opening direction, and the ∈-shaped flow channel connects the two inlet interfaces 1 with the outlet interface 2.

[0025] The bottom of the two-in-one return elbow is integrally extended with a conical boss 3, which can be used for welding a guide rod 7 (see Figure 7 ) to avoid adverse effects on the pipe wall of the two-in-one return elbow during the welding process.

[0026] like Figure 7 As shown, the present invention uses a two-in-one return elbow 4 applied to the radiation coil, and the two first-pass tubes 5 are respectively connected to the two inlet interfaces 1, so as to introduce the two fluids into the ∈-shaped flow channel and mix them evenly, and then they are discharged downstream by the second-pass tube 6 connected to the outlet joint 2.

[0027] A guide rod 7 is welded at the bottom of the two-in-one return elbow 4, and the guide rod 7 is placed in a guide groove (existing technology, not shown in the figure), which can ensure that the direction of elongation and creep of the furnace tube after heating is downward along the guide groove.

[0028] Since the two inlet interfaces 1 are arranged adjacent to each other, in order to avoid the generation of eddy currents, the inlet interface 1 close to the outlet interface 2 has a thickened convex corner 8 extending inwardly on the inner wall adjacent to the other inlet interface 1 .

[0029] In order to extend the service life, the inner wall surface of the outlet interface 2 gradually becomes thicker 9 from the outlet interface 2 inwards, making it more resistant to erosion.

[0030] The two-in-one return elbow 4 of the present invention does not occupy too much height space, thus effectively extending the straight tube length of the two first-pass tubes 5, increasing the specific surface area, and effectively reducing the number of components and the number of welds.

[0031] The above technical solution is only a typical implementation of the present invention. For those skilled in the art, it is easy to make various types of improvements or modifications based on the application method and principle disclosed in the present invention, and it is not limited to the method described in the above specific implementation of the present invention. Therefore, the above described method is only preferred and has no restrictive significance. The type of the two-in-one return elbow is not limited to the types listed in the figures. The two-in-one return elbow of the present invention can be used in various tube furnaces.

Claims

1. A two-in-one return elbow, used for connecting the furnace tubes of a tubular furnace in petrochemical production, characterized in that: It is an integrated structure with an ∈-shaped flow channel with the same opening direction inside. The ∈-shaped flow channel is respectively connected with two inlet interfaces and one outlet interface. The two inlet interfaces are arranged adjacent to each other and are arranged in the same direction as the outlet interfaces. The central axes of the two inlet interfaces and the outlet interface are located on the same plane, and the inlet interface close to the outlet interface has a thickened convex corner extending inwardly from the inner wall adjacent to the other inlet interface.

2. The two-in-one return elbow according to claim 1, characterized in that: The two-in-one return elbow is manufactured by casting, or by machining or 3D printing.

3. The two-in-one return elbow according to claim 1, characterized in that: A conical boss is integrally extended from the bottom of the two-in-one return elbow, and the conical boss is used for welding the guide rod.

4. The two-in-one return elbow according to claim 1, characterized in that: The wall surface of the outlet interface gradually becomes thicker from the outlet interface inwards.

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