A method for replacing the method flange of a large arc water chamber

Abstract

The present invention relates to the field of heat exchange device maintenance, and discloses a method for replacing a large arc-shaped water chamber method flange. First, the old method flange is cut off from the arc-shaped water chamber; then, a connecting plate with an arc contour is welded on one side of the new method flange to form a new flange assembly, and the other side of the new flange assembly is welded to the flange tooling; then, the new flange assembly and the flange tooling are placed on the welding and assembly platform and aligned. After the connecting plate matches the cutting end face of the arc-shaped water chamber, process tension bars are installed to fix the size and contour of the connecting plate; then, after the new flange assembly and the flange tooling are heat-treated, a sealing surface and bolt holes are machined on the new flange assembly separated from the flange tooling; finally, the new flange assembly and the flange tooling are placed on the welding and assembly platform and aligned, and the connecting plate in the new flange assembly is welded to the cutting end face of the arc-shaped water chamber. The method for replacing the method flange of the present invention avoids the influence of secondary heat treatment on the arc-shaped water chamber, and the cost of replacing the method flange and repairing the arc-shaped water chamber is greatly reduced.

Description

Technical Field

[0001] The present invention relates to the field of heat exchange device maintenance, and more particularly, to a method for replacing a large arc-shaped water chamber method flange. Background Art

[0002] An arc-shaped water chamber is a connecting structural member commonly used in a heat exchange device to inlet and outlet heat exchange media, withstand relatively high medium pressure, and convert the flow direction of the medium. Its connection structure with the heat exchanger main body is generally divided into two types: direct welding type and flange plus fastener type; in order to facilitate subsequent cleaning and maintenance of the heat exchanger main body, generally, the large heat exchanger main body and the water chamber basically adopt the connection method of method flange plus fasteners; actually, the method flange is a rectangular frame structure welded by four groups of flange strips, and its square structure has relatively large flexibility, and there are welding deformations, pressure test deformations, etc. during the manufacturing process. Among them, if the method flange is deformed too much during the pressure test, it cannot be installed and sealed subsequently, and thus cannot be used.

[0003] In the above situation, if the method flange is deformed too much, it is usually repaired by re-welding, heat treatment, and then machining the sealing surface and bolt holes of the flange as a whole. During the process, due to the large overall structural size of the arc-shaped water chamber, the repair costs of re-welding, heat treatment, machining, and transportation are very high, and the cycle is also long. Such a repair method greatly increases the production cost, reduces the production efficiency, and the secondary heat treatment may have an adverse impact on the overall structural strength of the water chamber. Summary of the Invention

[0004] The purpose of the present invention is to overcome the shortcomings of the background art and provide a method for replacing a large arc-shaped water chamber method flange.

[0005] The embodiments of the present invention are achieved by the following technical solutions:

[0006] A method for replacing a large arc-shaped water chamber method flange includes the following steps:

[0007] S1. Cut off the old method flange from the arc-shaped water chamber;

[0008] S2. Weld a connecting plate with an arc contour on one side of the new method flange to form a new flange assembly, wherein the connecting plate is used to connect with the cutting end face of the arc-shaped water chamber; weld the other side of the new flange assembly to the flange tooling;

[0009] S3. Place the new flange assembly and the flange tooling on the welding and assembly platform and align them; after adjusting the connecting plate to match the cutting end face of the arc-shaped water chamber, install process tie bars to fix the size and contour of the connecting plate;

[0010] S4. After heat-treating the new flange assembly and the flange tooling, remove the new flange assembly from the flange tooling;

[0011] S5. Machine the sealing surface and bolt holes on the new flange assembly;

[0012] S6. Weld the new flange assembly to the flange tooling again, place it on the welding and assembly platform and align it, and weld the connecting plate inside the new flange assembly to the cutting end face of the arc-shaped water chamber.

[0013] Preferably, in step S2, the new flange is welded by four groups of flange strips into a box structure connected end to end.

[0014] Preferably, in steps S3 and S6, the arc-shaped water chamber with the old flange removed needs to be hoisted above the new flange assembly located on the welding and assembly platform and assembled with the new flange assembly.

[0015] Preferably, the flange tooling includes a box structure welded by several steel plates, and several support steel pipes are welded inside the box structure.

[0016] Preferably, in step S1, there is an included angle between the cutting plane between the old flange and the arc-shaped water chamber and the end face of the old flange, and the included angle is an acute angle.

[0017] The technical solution of the embodiment of the present invention has at least the following advantages and beneficial effects:

[0018] 1. The size and weight of the new flange assembly are greatly reduced compared with the entire water chamber. Compared with directly heat-treating the old flange installed on the arc-shaped water chamber, the heat treatment and intermediate transfer costs are greatly reduced, and the influence of secondary heat treatment on the arc-shaped water chamber is avoided.

[0019] 2. The requirements for flange processing equipment are reduced. At the same time, the clamping difficulty during processing is also reduced, the processing efficiency is improved, the processing cost is reduced, and the quality of the sealing surface at the flange is also well guaranteed.

[0020] 3. The flange tooling used in the assembly process is convenient to obtain materials and has low cost. Description of the Drawings

[0021] Figure 1 It is a schematic diagram of the assembly relationship between the arc-shaped water chamber and the old flange of the present invention;

[0022] Figure 2 It is a schematic diagram of the assembly of the new flange assembly and the flange tooling of the present invention;

[0023] Figure 3 It is a schematic diagram of the structure of the flange tooling of the present invention;

[0024] Figure 4 It is a schematic diagram of the assembly relationship between the arc-shaped water chamber and the new flange assembly of the present invention;

[0025] Icons: 10 - Arc-shaped water chamber, 20 - Old flange, 3 - New flange assembly, 30 - New flange, 31 - Connecting plate, 40 - Flange tooling, 400 - Steel plate, 401 - Support steel pipe, a - Cutting plane. Detailed implementation mode

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Generally, the components of the embodiments of the present invention described and illustrated in the drawings here can be arranged and designed in various different configurations.

[0027] Refer to Figures 1 to 4 , the present invention discloses a method for replacing the method flange of a large arc-shaped water chamber 10, which includes the following steps:

[0028] S1. Cut off the old flange 20 from the arc-shaped water chamber 10; specifically, refer to Figure 1 , wherein, there is an included angle between the cutting plane a between the old flange 20 and the arc-shaped water chamber 10 and the end face of the old flange 20, and the included angle is an acute angle. After cutting, a part of the outer shell at the lower end of the arc-shaped water chamber 10 exists on the old flange 20.

[0029] S2. Process a set of new flanges 30. The new flanges 30 are welded into a box structure with the head and tail connected by four groups of flange strips, and then the new flanges 30 are assembled and spot-welded on the flange tooling 40; specifically, the new flanges 30 have opposite first and second end faces. A connecting plate 31 in an arc contour is spot-welded on the first end face of the new flange 30 to form a new flange assembly 3. The connecting plate 31 is mainly used to compensate for the part of the outer shell of the arc-shaped water chamber 10 remaining on the old flange 20 after cutting, so as to connect with the cutting end face of the arc-shaped water chamber 10 through the connecting plate 31;

[0030] In addition, the second end face of the new flange assembly 3 is fixedly connected to the flange tooling 40 by spot welding;

[0031] S3. Place the new flange assembly 3 and the flange tooling 40 on the welding platform. The welding platform is a common tooling platform and will not be elaborated here; then hoist the arc-shaped water chamber 10 after cutting off the old flange 20 above the new flange assembly 3 located on the welding platform. Then, adjust the inclination angle of the new flange assembly 3 and align it so that the lower end of the arc-shaped water chamber 10 can be accurately aligned and assembled with the connecting plate 31 inside the new flange assembly 3; after determining the contour and dimensions of the new flange assembly 3, move the arc-shaped water chamber 10 above the new flange assembly 3, and then install process tie bars inside the new flange assembly 3 to fix the dimensions and contour of the connecting plate 31 and the new flange 30;

[0032] S4. Heat-treat the new flange assembly 3 and the flange tooling 40 together. Depending on the process, the heat-treating method can be different. In this embodiment, the new flange assembly 3 and the flange tooling 40 are placed together in a heat-treatment furnace for stress relief annealing.

[0033] S5. After annealing is completed, separate the new flange assembly 3 from the flange tooling 40, and machine structures such as the sealing surface and bolt holes on the new flange assembly 3.

[0034] S6. Spot-weld the new flange assembly 3 with the machined sealing surface and bolt holes to the flange tooling 40 again, then place it on the welding platform, repeat the inclination adjustment, alignment, and assembly steps in step S3, and then weld the connecting plate 31 inside the new flange assembly 3 to the cut end surface at the lower end of the arc-shaped water chamber 10.

[0035] S7. After completing the welding of the connecting plate 31 to the arc-shaped water chamber 10, remove the flange tooling 40.

[0036] Refer to Figure 3 , the aforementioned flange tooling 40 includes a square box structure formed by welding several steel plates 400. The new flange assembly 3 is placed on the end surface of the flange tooling 40, and several support steel pipes 401 are welded inside the square box structure to maintain the structural strength of the flange tooling 40.

[0037] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for replacing the method flange of a large arc water chamber, characterized in that, It includes the following steps: S1. Cut off the old flange (20) from the arc-shaped water chamber (10); S2. Weld a connecting plate (31) with an arc contour on one side of the new flange (30) to form a new flange assembly (3), wherein the connecting plate (31) is used to connect with the cutting end face of the arc-shaped water chamber (10); weld the other side of the new flange assembly (3) to the flange tooling (40); S3. Place the new flange assembly (3) and the flange tooling (40) on the welding and assembling platform and align them; after adjusting the connecting plate (31) to match the cutting end face of the arc-shaped water chamber (10), install process tie bars to fix the size and contour of the connecting plate (31); S4. After heat-treating the new flange assembly (3) and the flange tooling (40), remove the new flange assembly (3) from the flange tooling (40); S5. Machine the sealing surface and bolt holes on the new flange assembly (3); S6. Weld the new flange assembly (3) and the flange tooling (40) again, place them on the welding and assembling platform and align them, and weld the connecting plate (31) inside the new flange assembly (3) to the cutting end face of the arc-shaped water chamber (10).

2. The method for replacing the large arc water chamber method flange according to claim 1, characterized in that: In step S2, the new flange (30) is welded by four groups of flange strips into a box structure connected end to end.

3. The method for replacing the large arc water chamber method flange according to claim 1, characterized in that: In steps S3 and S6, it is necessary to hoist the arc-shaped water chamber (10) with the old flange (20) cut off above the new flange assembly (3) located on the welding and assembling platform and assemble it with the new flange assembly (3).

4. The method for replacing the large arc water chamber method flange according to claim 1, characterized in that: The flange tooling (40) includes a box structure welded by several steel plates (400), and several support steel pipes (401) are welded inside the box structure.

5. The method for replacing the large arc water chamber method flange according to claim 1, characterized in that: In step S1, there is an included angle between the cutting plane (a) between the old flange (20) and the arc-shaped water chamber (10) and the end face of the old flange (20), and the included angle is an acute angle.

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