A manufacturing method for the stay ring and spiral case of a pumped-storage unit

Abstract

The present invention relates to the technical field of turbine manufacturing, and discloses a method for manufacturing a seat ring volute of a pumped storage unit. The method sets two left and right volute petals along the seat ring volute petal surface, cancels the structure of the petal surface transition plate + make-up section, and the two volute petals are cut and formed as a whole, and are assembled, welded and annealed in the factory, and then cut along the petal surface. The resolution surface of the volute petals is processed together with the assembly surface of the seat ring, and finally two seat ring volute petals are formed. The two seat ring volute petals are transported to the construction site, and are assembled and welded after being assembled on the construction site. The entire seat ring volute structure only has a circumferential weld on the assembly surface. Therefore, the method of the present invention can improve the assembly size accuracy and welding quality of the seat ring volute and compress the manufacturing cycle.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulic turbine manufacturing, and particularly relates to a manufacturing method for a stay ring spiral case of a pumped storage unit. Background Art

[0002] A pumped storage power station pumps water to a reservoir using the electric energy during the low load period of the power grid, and releases water to generate electricity in the lower reservoir during the peak load period of the power grid. It can convert the surplus electric energy during the low load period of the power grid into high-value electric energy during the peak period of the power grid. Currently, for the split surface of the stay ring spiral case of the existing pumped storage unit, a structure of a split surface transition plate + make-up joint (also called compensation joint) is adopted. Refer to the attached drawings of the specification Figure 1 , and its manufacturing process flow is as follows: The make-up joint and the transition plate are integrally blanked and formed, the transition plate is separated, the transition plate is assembled and welded, the stay ring is assembled into a circle, the make-up joint is prepared, and the make-up joint is assembled and welded on site. During the manufacturing process, due to the standard allowances existing in both the forming size of the make-up joint and the spiral case orifice surface size adjacent to the make-up joint, the make-up joint is prepared as a three-dimensional space curve. Therefore, the existing spiral case stay ring structure and production method have the following problems and difficulties:

[0003] (1) After the single-piece forming of the make-up joint, the transition plate needs to be separated. The transition plate is first welded to the stay ring and then welded to the make-up joint. There are many processes and it includes ineffective processes;

[0004] (2) When preparing the make-up joint, in order to ensure the dimensional accuracy of the inlet and outlet end faces, the two end faces need to be machined, and the transfer and machining time is long;

[0005] (3) It is difficult to prepare the make-up joint in the factory. Clearance and misalignment often occur at the out-of-tolerance points, and it is difficult to make the prepared dimensions of the make-up joint 100% qualified;

[0006] (4) The make-up joint is prepared twice, occupying a relatively long production straight cycle;

[0007] (5) It is difficult to assemble the make-up joint on site. The welding amount is large, the welding stress is large, the deformation of the stay ring after welding is large, and the on-site manufacturing cycle is long.

[0008] For example, the invention patent with the publication number CN114473377A, publication date of May 13, 2022, and invention title of "Manufacturing Method of Split-Type Spiral Case Stay Ring of Hydraulic Turbine" includes the following steps: a. Overall blanking of the dished head and compensating joint, then overall rolling forming of the dished head and compensating joint, and then cutting into single pieces respectively. Adjacent dished heads are a whole single piece; b. Grouping and circular lapping fixation of the two split spiral case stay rings, and then overall assembly and welding of the dished head at the split surface of the spiral case stay ring; c. Pre-assembly of the compensating joint at the split surface of the spiral case stay ring to complete the manufacturing of the spiral case stay ring. The present invention can avoid the problem of excessive misalignment during pre-assembly and assembly of the compensating joint and dished head of the split-type spiral case stay ring of large hydraulic turbines, ensure the stability of manufacturing quality, has a simple manufacturing process, and can effectively improve manufacturing efficiency.

[0009] Although the above-mentioned prior art proposes a brand-new manufacturing method for the spiral case stay ring, the spiral case stay ring in this patent still adopts the traditional structure of the patch joint and transition plate. Therefore, there are still problems and defects such as difficult preparation of the patch joint, difficult to guarantee the quality of the spiral case stay ring, and a relatively long overall manufacturing cycle. Summary of the Invention

[0010] In order to solve the problems and deficiencies existing in the above-mentioned prior art, the present invention proposes a manufacturing method for the stay ring spiral case of a pumped-storage unit. In this solution, two split spiral cases are arranged on the split surface of the stay ring spiral case, and the structure of the transition plate + patch joint at the split surface is cancelled. The two split spiral cases are integrally blanked and formed, welded and annealed in the factory, and then cut open along the split surface. The split surface of the split spiral case is processed together with the assembly surface of the stay ring, and finally two split stay ring spiral cases are formed. The two split stay ring spiral cases are transported to the construction site and welded and assembled after circular grouping. There is only a circumferential weld at the assembly surface in the entire stay ring spiral case structure. Therefore, the method of the present invention can improve the assembly dimension accuracy, welding quality, and compress the manufacturing cycle of the stay ring spiral case.

[0011] In order to achieve the above-mentioned invention purpose, the technical solution of the present invention is specifically as follows:

[0012] A manufacturing method for the stay ring spiral case of a pumped-storage unit. To meet the transportation requirements, the stay ring spiral case is assembled and welded in two splits at 180°, and specifically includes the following steps:

[0013] Step S1. Overall blanking of the spiral case section, and a preset cutting allowance is provided for the split spiral case section located at the split surface.

[0014] Step S2. Assemble the volute segments other than the split volute segment onto two split blank stay rings respectively, perform circular assembly and leveling on the two stay rings with assembled volute segments, then assemble the split volute segment onto the structure after circular assembly and leveling to finally form a complete stay ring volute blank. Then divide the stay ring volute blank into two split stay ring volute blanks, and anneal the two split stay ring volute blanks respectively;

[0015] Step S3. Machine the flat and beveled edges on the assembly surface of the split stay ring volute blank to finally form the split stay ring volute;

[0016] Step S4. Transport the two split stay ring volutes to the construction site, perform circular assembly on the two split stay ring volutes at the construction site, and finally weld the two split stay ring volutes along their assembly surfaces to form an integral body, completing the manufacturing of the stay ring volute.

[0017] Preferably, in step S1, the overall blanking means forming the volute segment by overall blanking on a numerically controlled machine tool.

[0018] Preferably, step S2 specifically includes the following contents:

[0019] Step S2.1. Assemble and weld the upper and lower ring plates with the stay vanes to obtain the split blank stay ring, machine the assembly surface of the split blank stay ring, and leave machining allowances at the assembly surfaces at both ends of the split blank stay ring;

[0020] Step S2.2. Mark the center line of the water guide mechanism of the split blank stay ring, take the intersection line of the theoretical assembly surface of the split blank stay ring and the plane of the upper or lower plane of the split blank stay ring as the X-axis, mark the Y-axis perpendicular to the X-axis, and use the center line of the water guide mechanism, the X-axis and the Y-axis as the assembly reference lines of the split blank stay ring;

[0021] Step S2.3. According to the assembly reference lines of the split blank stay ring, assemble all the volute segments other than the split volute segment onto the two split blank stay rings respectively and weld them to form two first-stage split stay ring volute blanks;

[0022] Step S2.4. Redraw the center line of the water guide mechanism and the X-axis and Y-axis of the split blank stay ring in the same way as in step S2.2;

[0023] Step S2.5. According to the redrawn center line of the water guide mechanism, the X-axis and the Y-axis in step S2.4, perform circular assembly and leveling on the two first-stage split stay ring volute blanks, and add spacers between the assembly surfaces of the two split blank stay rings. At this time, the two first-stage split stay ring volute blanks after circular assembly form the first-stage stay ring volute blank;

[0024] Step S2.6. Assemble the split volute section on the first-stage stay ring volute blank to form the second-stage stay ring volute blank, and at a distance of 150 mm from the assembly surface of the stay ring split blank on the inner circle side of the split volute section, weld and install anti-deformation supports.

[0025] Step S2.7. Complete half of the welding volume of the single-sided groove of the welds at all flat, horizontal, and vertical welding positions of the split volute section, and divide the second-stage stay ring volute blank into two halves along the cutting line on the split volute section to form two second-stage stay ring volute split blanks. The cutting surface formed after cutting and the assembly surface of the stay ring split blank together constitute the assembly surface of the second-stage stay ring volute split blank.

[0026] Step S2.8. Turn over a single second-stage stay ring volute split blank and complete all the welding of the root cleaning groove of the welds at all flat, horizontal, and vertical welding positions of the blank.

[0027] Step S2.9. Continue to turn over a single second-stage stay ring volute split blank and complete the remaining welding of the weld groove in Step S2.7.

[0028] Step S2.10. Check the dimensions of a single second-stage stay ring volute split blank, and anneal it after it is qualified.

[0029] Preferably, during annealing, add supports below the mouth surface of the stay ring volute split blank, adjust the elevation of the center of the mouth surface of the stay ring volute split blank, and the elevation difference from the center line elevation of the guide vane mechanism is ≤ 3 mm and the deviations of the two halves are consistent.

[0030] Preferably, the anti-deformation support is in a cross shape.

[0031] Preferably, the cutting line and the connection line of the centers of the two pads are in the same plane.

[0032] Preferably, in Step S3, machining the flat mouth and groove of the assembly surface of the stay ring volute split blank means machining the plane and groove of the cutting surface together with the assembly surface of the stay ring split blank.

[0033] Preferably, after the first-stage stay ring volute split blanks are grouped and leveled, the levelness deviation of the two blanks is ≤ 0.5 mm, the parallelism of the two blanks in the X-axis is ≤ 0.5 mm, and the coaxiality of the Y-axis is ≤ 0.5 mm.

[0034] Advantages of the present invention:

[0035] (1) By optimizing the structure of the traditional split surface transition plate + fitting joint into a spiral case split structure, and adopting the method of integral blanking, forming, welding, cutting, and machining of the spiral case split, the present invention can completely solve the quality risks of the assembly gap and misalignment dimension tolerance of the fitting joint in the existing stay ring spiral case structure of pumped storage units, reduce the assembly difficulty of the stay ring spiral case, reduce the welding amount, and improve the quality reliability of the manufacture of the stay ring spiral case. At the same time, it reduces the workload of on-site fitting, assembly, and welding in the factory and at the construction site, and compresses the manufacturing cycle.

[0036] (2) The integral blanking, forming, and welding of the spiral case split of the present invention, and then cutting and machining along the split surface, improve the consistency of the radius dimension of the spiral case split surface. Through UG simulation calculation, the misalignment amount of the spiral case at the split surface is about 1 mm, greatly improving the assembly dimension accuracy.

[0037] (3) When the spiral case of the present invention is cut open, a machining allowance is reserved on the cutting surface of the spiral case split, and the allowance is removed together with the assembly surface of the stay ring in the later stage. Therefore, the circumferential dimension accuracy of the spiral case split surface is greatly improved, and the gap of the spiral case split can be controlled within 1 mm.

[0038] (4) Under the same conditions of weld performance and flaw detection requirements, the present invention reduces the number of welds and the welding amount of the stay ring spiral case at the construction site, reduces the welding stress, and improves the dimension accuracy of the stay ring spiral case after on-site assembly and welding.

[0039] (5) The present invention transfers the longitudinal seam of the split surface transition plate + fitting joint with large stress in the existing stay ring spiral case structure from on-site welding to in-factory welding and annealing, improving the weld quality.

[0040] (6) The present invention reduces the processes of splitting the transition plate of the fitting joint, circularizing the stay ring, and pre-assembly in the factory, and also reduces the workload of on-site assembly and welding of the fitting joint. Therefore, the manufacturing cycle is greatly shortened, and the production efficiency of the enterprise is improved. Description of the Drawings

[0041] The foregoing and following specific descriptions of the present invention become clearer when read in conjunction with the following drawings, in which:

[0042] Figure 1 is a three-dimensional structure schematic diagram of the existing stay ring spiral case of a pumped storage unit in the background art;

[0043] Figure 2 is a plan schematic diagram of the existing stay ring spiral case of a pumped storage unit in the background art;

[0044] Figure 3 is a welding schematic diagram of the existing stay ring spiral case of a pumped storage unit in the background art;

[0045] Figure 4This is a three-dimensional structure schematic diagram of the stay ring and spiral case of the pumped-storage unit of the present invention;

[0046] Figure 5 This is a plane schematic diagram of the stay ring and spiral case of the pumped-storage unit of the present invention;

[0047] Figure 6 This is a welding schematic diagram of the stay ring and spiral case of the pumped-storage unit of the present invention. Specific embodiments

[0048] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the following will further illustrate the technical solutions for achieving the invention purpose of the present invention through several specific embodiments. It should be noted that the technical solutions claimed by the present invention include but are not limited to the following embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those skilled in the art without creative efforts shall fall within the protection scope of the present invention.

[0049] The spiral case of the existing pumped-storage unit adopts a structure of split surface transition plate + fitting joint (also called compensation joint), and its structure can be referred to in the attached drawings of the specification Figure 1 - attached Figure 3 as shown. The main purposes of this structural design are two: one is to solve the split transportation of the stay ring and spiral case, and the other is to solve the accumulation of circumferential dimension deviations after the assembly and welding of multiple-section spiral cases. Its manufacturing process flow is roughly as follows:

[0050] (1) The fitting joint and the transition plate are integrally blanked and formed into a C-shaped joint; (2) The transition plate is separated; (3) The stay ring is leveled and circularly assembled; (4) The transition plate is assembled and welded; (5) The fitting joint is roughly prepared; (6) The transition plate is cut along the split surface; (7) The stay ring is machined; (8) The stay ring is circularly assembled; (9) The fitting joint is precisely prepared; (10) The fitting joint is assembled and welded on the construction site.

[0051] During the manufacturing process, due to the standard allowances of the forming dimensions of the fitting joint and the spiral case mouth surface adjacent to the fitting joint, and the fact that the fitting joint is prepared as a three-dimensional space curve, etc., it is difficult to precisely prepare the fitting joint, the quality is difficult to guarantee, and the manufacturing cycle is relatively long. Therefore, the manufacturing difficulties of the existing spiral case stay ring structure are summarized as follows:

[0052] (1) After the single-piece forming of the fitting joint, the transition plate needs to be separated. The transition plate is first welded to the stay ring and then welded to the fitting joint, with many processes and including ineffective processes;

[0053] (2) When preparing the fitting joint, in order to ensure the dimensional accuracy of the inlet and outlet end faces, the two end faces need to be machined, and the transfer and processing time is long;

[0054] (3) It is difficult to prepare the fitting joint in the factory, and the clearance and misalignment often appear as out-of-tolerance points, and it is difficult to make the prepared dimensions of the fitting joint 100% qualified;

[0055] (4) The make-up section is prepared twice, occupying a relatively long production cycle.

[0056] (5) It is difficult to assemble the make-up section at the construction site. The welding volume is large, the welding stress is large, the stay ring deforms greatly after welding, and the manufacturing cycle at the construction site is long.

[0057] Based on this, this embodiment provides a manufacturing method and structure for the stay ring and spiral case of a pumped-storage unit. In this solution, two spiral case segments are arranged on the split surface of the stay ring and spiral case, and the structure of the transition plate + make-up section on the split surface is cancelled. The two spiral case segments are cut and formed integrally in the factory, welded and annealed in the factory, and then cut along the split surface. The split surface of the spiral case segment is machined together with the assembly surface of the stay ring, and finally two stay ring and spiral case segments are formed. The two stay ring and spiral case segments are transported to the construction site and welded and assembled after being assembled into a circle at the construction site. There is only a circumferential weld on the assembly surface in the entire stay ring and spiral case structure.

[0058] In this embodiment, it should be noted first that the stay ring and spiral case is a combined structure of a stay ring and a spiral case, where;

[0059] The spiral case as a whole is a spiral tube structure. The spiral case has a head end and a tail end, and the head end and the tail end intersect, but the head end and the tail end of the spiral case are connected but not communicated. Further, the spiral case is assembled and welded by a number of C-shaped spiral case sections. Among them, the spiral case section located at the split surface is called the split spiral case section in this embodiment.

[0060] The stay ring is assembled and spliced by two 180-degree stay ring segments. The stay ring is fixedly connected to the spiral case arranged above it by welding, and the head end and the tail end of the stay ring overlap with the head end and the tail end of the spiral case. An opening is provided on the inner circumferential side of the spiral case for installing the stay ring. The stay ring extends along the inner circumference direction of the spiral case and is welded and connected in the opening. Further, a single stay ring is composed of two parallel upper and lower ring plates and the stay vanes located between the two ring plates. A number of stay vanes are evenly distributed at equal intervals along the circumferential direction of the spiral case starting from the head end of the spiral case, which can achieve the effect of uniform water supply; furthermore, the stay vanes are inclined at a certain angle along the water flow direction, which can buffer the impact force of the water flow to a certain extent.

[0061] The embodiment of the present invention discloses a manufacturing method for the stay ring and spiral case of a pumped-storage unit. To meet the transportation requirements, the stay ring and spiral case is first processed and formed into two 180-degree split structures in the factory, and then the two 180° split structures are transported to the construction site. At the construction site, the two split structures are assembled into a circle and welded and assembled, and finally a complete spiral stay ring and spiral case is formed. The structure and welding method of the entire stay ring and spiral case can be referred to in the attached Figures 4 - 6 . This method specifically includes the following steps:

[0062] Step S1. Numerically control the overall blanking and forming of all volute segments required for assembly by a numerically controlled machine tool to form a number of volute segments in a C-shaped structure. Among them, a machining allowance is preset for the two split volute segments located at the split surface of the stay ring volute during blanking and forming.

[0063] In this embodiment, the machining allowance is generally 30 mm.

[0064] Step S2. In the processing factory, assemble all volute segments except the split volute segments on the two split stay ring blanks respectively. Then, perform circular alignment and leveling on the two stay ring split blanks assembled with volute segments. Next, assemble the split volute segments on the structure after circular alignment and leveling. The two stay ring split blanks form a stay ring blank after circular alignment. All the volute segments arranged on the stay ring blank form a volute blank. Finally, the stay ring blank and the volute blank form a complete stay ring volute blank. Finally, divide the stay ring volute blank into two stay ring volute split blanks, and anneal the two stay ring volute split blanks respectively.

[0065] More specifically, step S2 includes the following contents:

[0066] Step S2.1. Assembly of the stay ring split ring plate and the stay vanes and rough machining of the assembly surface: Weld the upper ring plate and the lower ring plate of the stay ring split structure to the stay vanes through a welding device. After welding, obtain the corresponding stay ring split blank. Then, transfer and process the assembly surface of the stay ring split blank, leaving 7 mm of subsequent machining allowance at each of the two ends of the assembly surface.

[0067] In this embodiment, it should be noted that since the stay ring of the stay ring volute is composed of two stay ring splits spliced together, two stay ring split blanks will be processed during machining.

[0068] In this embodiment, it should also be noted that step S2.1 is the processing process of the stay ring split blank, and its processing process with the volute segment in step S1 can be carried out simultaneously in the factory, and there is no strict sequence between the two.

[0069] Step S2.2. Mark the center line of the water guide mechanism of a single stay ring split blank. Take the intersection line of the theoretical assembly surface of the stay ring split blank and the plane of the upper or lower plane of the stay ring split blank as the X-axis, and mark the Y-axis perpendicular to the X-axis. Take the center line of the water guide mechanism, the X-axis and the Y-axis as the assembly reference lines of the stay ring split blank;

[0070] In this embodiment, it should be noted that the theoretical assembly surface of the stay ring split blank refers to the plane passing through the center of the stay ring split blank and this plane is in the vertical plane.

[0071] In this embodiment, it should also be noted that the upper plane of the split blank of the stay ring refers to the upper plane (i.e., the upper surface) of the upper ring plate, and the lower plane of the split blank of the stay ring refers to the lower plane (i.e., the lower surface) of the lower ring plate.

[0072] In this embodiment, the assembly reference lines of both split blanks of the stay ring are drawn according to the operation process of step S2.2.

[0073] Step S2.3. According to the assembly reference lines of the split blanks of the stay ring drawn in step S2.2, all the volute segments except the split volute segment are respectively assembled onto the two split blanks of the stay ring to form two first-stage stay ring volute split blanks.

[0074] Step S2.4. Redraw the center line of the water guide mechanism and the X-axis and Y-axis of the split blank of the stay ring in the same manner as in step S2.2, and use them as the new assembly reference lines.

[0075] Step S2.5. According to the scribing results of step S2.4, in accordance with the principle that the center lines of the two split water guide mechanisms are in the same plane with a levelness deviation ≤ 0.5 mm, the parallelism of the X-axis ≤ 0.5 mm, and the coaxiality of the Y-axis ≤ 0.5 mm, level and round the two first-stage stay ring volute split blanks, and add pads between the assembly surfaces of the two first-stage stay ring volute split blanks. After the two first-stage stay ring volute split blanks are adjusted and rounded, they form the first-stage stay ring volute blank.

[0076] In this embodiment, it should be noted that the essence of the pad structure added between the two blanks is installed between the two split blanks of the stay ring, located at the assembly surfaces of the two split blanks of the stay ring. Each split blank of the stay ring has two assembly surfaces. Therefore, after the two split blanks of the stay ring are leveled and rounded, there are two pads in total; after being adjusted and rounded, the pads do not have a connection relationship with the assembly surfaces of the two split blanks of the stay ring on both sides, but are only stuck between the two assembly surfaces, and the entire split blank of the stay ring is free without any constraints.

[0077] Furthermore, after the two first-stage stay ring volute split blanks are leveled and rounded, the two split blanks of the stay ring are equivalent to forming a complete stay ring blank. However, at this time, the split volute segment at the split surface on the stay ring blank has not been installed in place, so a complete stay ring volute blank structure has not been formed yet.

[0078] Step S2.6. Assemble the split volute segment onto the first-stage stay ring volute blank. At this time, all the volute segments on the entire stay ring blank are installed in place, and all the volute segments form the volute blank on the stay ring blank. The volute blank and the lower stay ring blank together form the second-stage stay ring volute blank, and at a distance of 150 mm from the assembly surface of the split blank of the stay ring on the inner circle side of the split volute segment, install and weld anti-deformation supports.

[0079] In this embodiment, it should be noted that at this time, after the assembly in step 2.6, the formed second-stage stay ring volute blank is the final complete stay ring volute blank structure. Based on this, the final assembly welding, cutting, and grinding can be carried out to obtain two split stay ring volute structures.

[0080] In this embodiment, it should also be noted that the anti-deformation support is in a cross shape.

[0081] Step S2.7. Complete half of the welding amount of the single-sided bevel groove of all horizontal, vertical, and flat welding positions of the split volute section. Divide the second-stage stay ring volute blank along the cutting line into two parts. The cutting line is located on the split volute section. After cutting the second-stage stay ring volute blank, two second-stage stay ring volute split blanks are formed. The cutting surface and the assembly surface of the stay ring split blank together constitute the assembly surface of the second-stage stay ring volute split blank.

[0082] In this embodiment, it should be noted that the connecting line between the cutting line and the centers of the two pads at the stay ring assembly surface is in the same plane.

[0083] In this embodiment, it should also be noted that the cutting process is essentially to cut the split volute at the split surface into two parts. Since the two lower stay ring blanks are not connected together at this time,

[0084] In this embodiment, the assembly surface of the second-stage stay ring volute split blank is equivalent to the split surface blank of the later stay ring volute structure. The final split surface can be obtained only after processing this assembly surface.

[0085] Step S2.8. Turn over a single second-stage stay ring volute split blank and complete all welding of the root face bevel groove of all horizontal, vertical, and flat welding positions of the blank.

[0086] In this embodiment, the "turning over" means turning the structure 180 degrees.

[0087] Step S2.9. Continue to turn over a single second-stage stay ring volute split blank and complete the remaining welding of the weld bevel groove in step S2.7.

[0088] Step S2.10. Check the dimensions of a single second-stage stay ring volute split blank. After passing the inspection, anneal it.

[0089] In this embodiment, it should be noted that during annealing, add supports below the mouth surface of the split stay ring volute, adjust the elevation of the center of the mouth surface of the second-stage stay ring volute split blank, and the elevation difference from the center line elevation of the water guide mechanism is ≤ 3 mm and the two parts are biased in the same direction.

[0090] In this embodiment, it should also be noted that when either the split volute section located at the resolution surface position or the remaining volute sections are assembled onto the stay ring, there are assembly welds between the volute sections and adjacent volute sections, as well as assembly welds between the volute sections and the stay ring below. After welding, they finally form a whole.

[0091] Step S3. Process the flat ends and bevels of the assembly surfaces of the two stay ring volute split blanks respectively, and finally form the stay ring volute splits.

[0092] In this embodiment, processing the flat ends and bevels of the assembly surfaces of the stay ring volute split blanks means processing the plane and bevel of the cutting surface of the volute together with the assembly surface of the stay ring split blank. After processing, the stay ring volute splits are obtained. The processed surface is the assembly surface of the stay ring volute splits and also the resolution surface of the entire stay ring volute structure.

[0093] In this embodiment, Step S2 and Step S3 are the entire processing process of the stay ring volute splits. The above two steps are both completed in the processing factory. After the processed stay ring volute splits are transported to the construction site, only circular assembly is required. The specific circular assembly is Step S4 of this solution, which is as follows.

[0094] Step S4. Transport the two stay ring volute splits to the construction site, perform circular assembly on the two stay ring volute splits at the construction site, and finally weld the two stay ring volute splits along the assembly surfaces of the two stay ring volute splits to form a whole, completing the manufacture of the stay ring volute.

[0095] For the stay ring volute structure formed by adopting the above solution, the split surface transition plate + patch joint structure of the volute is cancelled. The two volute splits are integrally blanked and formed, welded and annealed in the factory, and then cut open along the split surface. The resolution surface of the volute splits is processed together with the assembly surface of the stay ring, and finally two stay ring volute splits are formed. The two stay ring volute splits are transported to the construction site and welded and assembled after circular assembly at the construction site. There is only a circumferential weld at the assembly surface in the entire stay ring volute structure. Therefore, the manufacturing method of the present invention can improve the assembly dimension accuracy, welding quality and compress the manufacturing cycle of the stay ring volute.

[0096] The above are only the preferred embodiments of the present invention, and do not impose any form of limitation on the present invention. Any simple modification or equivalent change made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A manufacturing method for the stay ring and spiral case of a pumped-storage unit. To meet the transportation requirements, the stay ring and spiral case are assembled and welded in two split parts divided at 180°. It is characterized in that It includes the following steps: Step S1. Perform overall blanking on the volute segments, and preset a fitting and cutting allowance for the split volute segments at the split surface; Step S2. Assemble the volute segments other than the split volute segments onto two split blank stay rings respectively, group and level the two stay rings with assembled volute segments, then assemble the split volute segments onto the grouped and leveled structure to finally form a complete stay ring volute blank. Then divide the stay ring volute blank into two split stay ring volute blanks, and anneal the two split stay ring volute blanks respectively; Step S3. Machine the flat and beveled openings on the assembly surfaces of the split stay ring volute blanks to finally form split stay ring volutes; Step S4. Transport the two split stay ring volutes to the construction site, group the two split stay ring volutes at the construction site, and finally weld the two split stay ring volutes along the assembly surfaces to form a whole, completing the manufacture of the stay ring volute.

2. The manufacturing method of the stay ring and spiral case of a pumped-storage unit according to claim 1, characterized in that In the said step S1, overall blanking means forming the volute segments through overall blanking by a numerical control machine tool.

3. A manufacturing method of a stay ring and spiral case of a pumped storage unit according to claim 1, characterized in that, The said step S2 specifically includes the following contents: Step S2.

1. Assemble and weld the upper and lower ring plates and the stay vanes to obtain a split blank stay ring, machine the assembly surfaces of the split blank stay ring, and leave machining allowances at the assembly surfaces at both ends of the split blank stay ring; Step S2.

2. Mark the center line of the water guide mechanism of the split blank stay ring, take the intersection line of the theoretical assembly surface of the split blank stay ring and the plane of the upper or lower plane of the split blank stay ring as the X-axis, mark the Y-axis perpendicular to the X-axis, and use the center line of the water guide mechanism, the X-axis and the Y-axis as the assembly reference lines of the split blank stay ring; Step S2.

3. According to the assembly reference lines of the split blank stay ring, assemble all the volute segments other than the split volute segments onto the two split blank stay rings respectively and weld them to form two first-stage split stay ring volute blanks; Step S2.

4. Redraw the center line of the water guide mechanism of the split blank stay ring and the X-axis and Y-axis in the way of step S2.2; Step S2.

5. According to the redrawn center line of the water guide mechanism, X-axis and Y-axis in step S2.4, group and level the two first-stage split stay ring volute blanks, and set pads between the assembly surfaces of the two split blank stay rings. At this time, the two grouped first-stage split stay ring volute blanks form a first-stage stay ring volute blank; Step S2.

6. Assemble the split volute segments onto the first-stage stay ring volute blank to form a second-stage stay ring volute blank, and weld anti-deformation supports on the inner circle side of the split volute segments; Step S2.

7. Complete half of the welding amount of the single-sided beveled joints at all flat, horizontal and vertical welding positions of the split volute segments, divide the second-stage stay ring volute blank into two pieces along the cutting line to form two second-stage split stay ring volute blanks, and the cutting surface and the assembly surface of the split blank stay ring together form the assembly surface of the second-stage split stay ring volute blank; Step S2.

8. Turn over a single second-stage split stay ring volute blank and complete all the welding of the root clearing beveled joints at all flat, horizontal and vertical welding positions of the blank; Step S2.

9. The single-piece second-stage stay ring spiral case split blank continues to be turned over to complete the remaining welding of the weld groove in Step S2.

7. Step S2.

10. Check the dimensions of the single-piece second-stage stay ring spiral case split blank, and anneal it after it is qualified.

4. A manufacturing method of a stay ring and spiral case of a pumped storage unit according to claim 1, characterized in that, During annealing, add supports below the mouth surface of the stay ring spiral case split blank, and adjust the elevation of the center of the mouth surface of the stay ring spiral case split blank so that the elevation difference from the center line elevation of the wicket gate mechanism is ≤ 3 mm and the two splits are biased in the same direction.

5. A manufacturing method of a stay ring and spiral case of a pumped-storage unit according to claim 3, characterized in that, The anti-deformation support is in a cross shape.

6. A manufacturing method of a stay ring and spiral case of a pumped storage unit according to claim 3, characterized in that, The cutting line and the connection line of the centers of the two pads are in the same plane.

7. A manufacturing method of a stay ring and spiral case of a pumped storage unit according to claim 3, characterized in that, In Step S2.6, install and weld the anti-deformation support at a distance of 150 mm from the assembly surface of the stay ring split blank on the inner circle side of the split spiral case section.

8. A manufacturing method of a stay ring and spiral case of a pumped-storage unit according to claim 1, characterized in that, In Step S3, machining the flat mouth and groove on the assembly surface of the stay ring spiral case split blank means machining the cutting surface into a plane and a groove together with the assembly surface of the stay ring split blank.

9. A manufacturing method of a stay ring and spiral case of a pumped storage unit according to claim 3, characterized in that, After the first-stage stay ring spiral case split blanks are assembled into a circle and leveled, the levelness deviation between the two blanks is ≤ 0.5 mm, the parallelism of the two blanks in the X-axis is ≤ 0.5 mm, and the coaxiality of the two blanks in the Y-axis is ≤ 0.5 mm.

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