A connection structure for outlet of pressure relief pipe of water turbine top cover

Abstract

The utility model discloses a turbine top cover pressure relief pipe outlet connection structure, which mainly solves the problem that the existing top cover pressure relief pipe outlet connection method is prone to cracks, water leakage and difficulty in maintenance. The structure includes a bend pipe welded to the outlet of the top cover pressure relief pipe, and a short pipe connected to the bend pipe through a pipeline connection structure; wherein the other end of the short pipe is connected to the external pipeline by a flange. The utility model can quickly disassemble the top cover pressure relief pipe drainage pipe by disassembling and assembling the clamp and the short pipe flange, thereby shortening the maintenance period. This clamp-type flexible shoulder-type pipe joint connection structure is a soft connection method, which can avoid problems such as seal water seepage, seal rupture, weld cracking, etc. caused by vibration of the pipeline. There is no need to cut the pipeline, and there is no damage to the pipeline material. Therefore, it is suitable for promotion and application.

Description

Technical Field

[0001] The utility model belongs to the technical field of top covers of water turbine generator sets, and in particular relates to an outlet connection structure of a pressure relief pipe of a water turbine top cover. Background Art

[0002] The Zipingpu hydroelectric generator set was put into operation in 2006. The original design unit was Dongfang Electric Corporation. In order to effectively reduce the axial water thrust during the operation of the unit and improve the safety and reliability of the thrust bearing operation, four DN200 pressure relief pipes were installed on the top cover to discharge the pressure water between the top cover and the runner to the tail water. This design is difficult to disassemble and assemble, prone to leakage, and difficult to repair, resulting in a waste of construction time and economic losses.

[0003] The original top cover pressure relief pipe outlet connection method is difficult to disassemble and assemble. The original top cover pressure relief pipe outlet and the drainage pipe are connected by a flange hard connection method with a matching short pipe. The flanges are all raised face flanges. This connection method has no expansion margin. The sealing gaskets on the flanges on both sides of the short pipe need to be forcibly disassembled and assembled by hydraulic expansion, jacking, crane pulling, etc. during installation and disassembly, which is easy to cause the short pipe to deform, which is not conducive to the next reinstallation and slows down the work progress.

[0004] The reason why the original top cover pressure relief pipe outlet connection method is prone to cracks: the top cover of the hydro-turbine generator set vibrates greatly. This design uses a hard connection, and the vibration is transmitted along the pipeline. Under long-term vibration, the weak points on the pipeline are prone to cracks. The top cover pressure relief pipe of Zipingpu Power Plant has experienced many problems such as flange seal water seepage, seal rupture, and weld cracking.

[0005] The original top cover pressure relief pipe outlet connection method is difficult to inspect and repair because the space here is small, making disassembly and assembly difficult and inconvenient. The length of the elbow and short pipe is short. To deal with defects such as sealing water seepage and weld cracking water seepage, the elbow vertical pipe needs to be cut off before it can be removed. The cuttable length of the elbow vertical pipe is only 55mm. Multiple cutting and welding at the same position will cause coarse grains in the heat-affected zone, which is easy to form brittle and hard structures, reduce the plasticity and toughness of the weld, and thus create new safety hazards. The top cover pressure relief pipe cut off during defect treatment is shown in the figure. Figure 2 The top cover pressure relief pipeline is located at an elevation lower than the tailwater level, so the unit must be shut down to lower the water inlet gate and tailwater gate, and the water in the tailwater pipe must be removed before it can be handled. The construction period is at least 3 days, causing huge economic losses. Utility Model Content

[0006] The utility model aims to provide a turbine top cover pressure relief pipe outlet connection structure, which mainly solves the problem that the existing top cover pressure relief pipe outlet connection method is prone to cracks, water leakage and maintenance difficulties.

[0007] In order to achieve the above purpose, the technical solution adopted by the utility model is as follows:

[0008] A turbine top cover pressure relief pipe outlet connection structure, comprising a bent pipe welded to the top cover pressure relief pipe outlet, and a short pipe connected to the bent pipe through a pipeline connection structure; wherein the other end of the short pipe is connected to an external pipeline by a flange;

[0009] The curved pipe comprises a curved pipe transverse pipe and a curved pipe vertical pipe, one end of the curved pipe transverse pipe is vertically connected to the curved pipe vertical pipe, the other end of the curved pipe transverse pipe is connected to a short pipe, and bosses are provided at the ends where the curved pipe transverse pipe and the short pipe are connected.

[0010] Furthermore, in the utility model, the pipeline connection structure adopts a clamp-type flexible shoulder-type pipe joint connection structure, and a 3mm gap is set at the ends of the two pipelines of the bent pipe cross pipe and the short pipe. The connection between the bent pipe cross pipe and the short pipe is achieved by clamping the bosses at the ends of the bent pipe cross pipe and the short pipe, and the clamp is fastened by the clamp fastening bolt to achieve a fastened connection.

[0011] Furthermore, in the utility model, a circle of sealing gasket with a C-shaped cross section surrounds the inner wall of the middle part of the clamp and the outer walls of the bosses of the curved pipe, the cross pipe and the short pipe.

[0012] Furthermore, in the present invention, the clamp is a double-ear clamp, and each side is fastened with 2 sets of clamp fastening bolts, and a total of 4 sets of clamp fastening bolts are used.

[0013] Furthermore, in the utility model, the flange for connecting the short pipe with the external pipeline adopts a tongue-and-groove flange, and is sealed with a rubber round strip sealing ring.

[0014] Compared with the prior art, the utility model has the following beneficial effects:

[0015] The short tube and the external tube of the utility model adopt tongue and groove flanges, and the sealing adopts a rubber round strip sealing ring; the connection method between the elbow and the short tube is changed, and a clamp-type flexible shoulder-type pipe joint is adopted for connection, leaving a 3mm gap between the elbow and the short tube, and bosses are processed at the ends of the elbow cross tube and the short tube, and the elbow and the short tube are connected by a clamp and a C-type sealing ring. When in use, the top cover pressure relief pipe and drainage pipe can be quickly disassembled by disassembling the clamp and the short tube flange, shortening the maintenance period. This clamp-type flexible shoulder-type pipe joint connection structure is a soft connection method, which can avoid problems such as seal water seepage, seal rupture, and weld cracking caused by vibration of the pipeline. There is no need to cut the pipeline, and there is no damage to the pipeline material. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the overall structure of the utility model.

[0017] Figure 2 It is a schematic diagram of the cross-sectional structure of the connection between the curved pipe, the horizontal pipe and the short pipe in the utility model.

[0018] The names corresponding to the reference numerals are:

[0019] 1- elbow, 2- pipe connection structure, 3- short pipe, 4- flange, 5- boss, 6- clamp, 7- clamp fastening bolt, 8- sealing gasket, 9- top cover, 10- elbow horizontal pipe, 11- elbow vertical pipe. DETAILED DESCRIPTION

[0020] The present invention is further described below in conjunction with the accompanying drawings and embodiments. The present invention includes but is not limited to the following embodiments.

[0021] Example

[0022] like Figure 1 , 2 As shown, the utility model discloses a turbine top cover pressure relief pipe outlet connection structure, comprising an elbow 1 welded to the pressure relief pipe outlet of the top cover 9, and a short pipe 3 connected to the elbow 1 through a pipeline connection structure 2; wherein the other end of the short pipe 3 is connected to the external pipeline by a flange 4. The connected flange 4 is a tongue-and-groove flange, and is sealed by a φ8 rubber round strip sealing ring.

[0023] The bend pipe 1 includes a bend transverse pipe 10 and a bend vertical pipe 11. One end of the bend transverse pipe 10 is vertically connected to the bend vertical pipe 11, and the other end of the bend transverse pipe 10 is connected to the short pipe 3. The ends where the bend transverse pipe 10 and the short pipe 3 are connected are both provided with bosses 5.

[0024] In this embodiment, the pipeline connection structure 2 adopts a clamp-type flexible shoulder-type pipe joint connection structure, and a 3mm gap is set between the two pipe ends of the elbow cross pipe 10 and the short pipe 3. The elbow cross pipe 10 and the short pipe 3 are connected by clamping the boss 5 at the end of the elbow cross pipe 10 and the short pipe 3 by the clamp 6, and the clamp 6 is fastened by the clamp fastening bolt 7. Among them, the clamp 6 uses a double-ear clamp, and each side is fastened with 2 sets of clamp fastening bolts 7, and a total of 4 sets of clamp fastening bolts 7 are used. A circle of sealing gaskets 8 with a C-shaped cross section surrounds the inner wall of the middle part of the clamp 6 and the outer wall of the boss 5 of the elbow cross pipe and the short pipe.

[0025] Installation and use method of this utility model:

[0026] 1. For the first installation, select a stainless steel seamless steel pipe with a wall thickness of not less than 10mm for turning, leave a boss with a width of 20mm and a height of 6mm at the pipe mouth, and process 2 steel pipes with bosses. Customize the clamps and C-type sealing rings according to the actual size on site. Calculate the length of the elbow and short pipe according to the actual size on site. Cut off the original top cover pressure relief pipe outlet elbow as a whole, use the steel pipe with bosses to re-pipe and make the elbow, and the boss is located at the end of the horizontal pipe. Use the steel pipe with bosses to re-pipe and make the short pipe, and the boss is located at the end of the short pipe. First, pipe the short pipe and flange for piping welding. The short pipe and the external pipe use tongue and groove flanges, install the short pipe flange and φ8 rubber round strip sealing ring, and put the C-type sealing ring on the short pipe; when welding the elbow, ensure that the elbow transverse pipe is consistent with the center line of the short pipe, and ensure that the gap between the end of the elbow transverse pipe and the end of the short pipe is 3mm; put the sealing ring on the two bosses, put the clamp on the boss, tighten the bolts, and complete the installation.

[0027] 2. After installation, when disassembling for inspection, remove the 4 fastening bolts of the clamp, take out the clamp, push the C-type sealing ring away from the interface, remove the short pipe flange bolts and remove the short pipe to complete the disassembly. When reinstalling for inspection, put the C-type sealing ring on the short pipe or the elbow cross pipe, then install the short pipe and the φ8 sealing ring, then put the sealing ring on the two bosses, put the clamp on the boss, tighten the bolts, and complete the reinstallation.

[0028] The utility model can quickly disassemble the top cover pressure relief pipe and drainage pipe by disassembling the clamp and the short pipe flange, shortening the maintenance period. The clamp-type flexible shoulder-type pipe joint connection structure is a soft connection method, which can avoid problems such as seal water seepage, seal rupture, weld cracking, etc. caused by pipeline vibration. There is no need to cut the pipeline, and there is no damage to the pipeline material. Therefore, compared with the prior art, the utility model has substantial characteristics and progress.

[0029] The above embodiment is only one of the preferred implementation modes of the present utility model and should not be used to limit the protection scope of the present utility model. Any changes or modifications that are made to the main design concept and spirit of the present utility model without any substantive significance, as long as the technical problems solved are still consistent with the present utility model, should be included in the protection scope of the present utility model.

Claims

1. A turbine top cover pressure relief pipe outlet connection structure, characterized in that: It comprises a bent pipe (1) welded to the outlet of the pressure relief pipe of the top cover, and a short pipe (3) connected to the bent pipe (1) via a pipeline connection structure (2); wherein the other end of the short pipe (3) is connected to an external pipeline via a flange (4); The curved pipe (1) comprises a curved pipe transverse pipe (10) and a curved pipe vertical pipe (11); one end of the curved pipe transverse pipe (10) is vertically connected to the curved pipe vertical pipe (11); the other end of the curved pipe transverse pipe (10) is connected to a short pipe (3); and bosses (5) are provided at the ends where the curved pipe transverse pipe (10) and the short pipe (3) are connected.

2. A turbine top cover pressure relief pipe outlet connection structure according to claim 1, characterized in that: The pipeline connection structure (2) adopts a clamp-type flexible shoulder-type pipe joint connection structure, and a 3mm gap is set at the ends of the two pipes of the curved pipe cross pipe (10) and the short pipe (3). The curved pipe cross pipe (10) and the short pipe (3) are connected by clamping the bosses (5) at the ends of the curved pipe cross pipe (10) and the short pipe (3). The clamp (6) is fastened by clamp fastening bolts (7) to achieve a fastened connection.

3. A turbine top cover pressure relief pipe outlet connection structure according to claim 2, characterized in that: A sealing gasket (8) with a C-shaped cross section surrounds the inner wall of the middle of the clamp (6) and the outer walls of the bosses (5) of the curved pipe, the cross pipe and the short pipe.

4. A turbine top cover pressure relief pipe outlet connection structure according to claim 3, characterized in that: The clamp (6) is a double-ear clamp, and each side is fastened with two sets of clamp fastening bolts (7), and a total of four sets of clamp fastening bolts (7) are used.

5. A turbine top cover pressure relief pipe outlet connection structure according to claim 4, characterized in that: The flange (4) for connecting the short pipe (3) with the external pipeline adopts a tongue-and-groove flange and is sealed with a rubber round seal ring.

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