Manufacturing method for seat ring volute of pumped storage unit

Abstract

The present invention relates to the technical field of water turbine manufacturing. Disclosed is a manufacturing method for a seat ring volute of a pumped storage unit. According to the present method, a left volute part and a right volute part are arranged along a split surface of the seat ring volute; the structure of split surface transition plate plus expansion joint is cancelled; the two volute parts are subjected to integral blanking and forming, are welded and annealed in the factory, and are then cut along the split surface; the split surface between the volute parts is machined together with an assembly surface of a seat ring to finally form two seat ring volute parts; the two seat ring volute parts are transported to a construction site, and are assembled and welded after being combined into a circle 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 precision and welding quality of the seat ring volute, and shorten the manufacturing period thereof.

Description

A method for manufacturing a seat ring volute of a pumped storage unit Technical Field

[0001] The present invention relates to the technical field of water turbine manufacturing, and in particular to a method for manufacturing a seat ring and volute of a pumped storage unit. Background Art

[0002] A pumped storage power station uses electricity during low power load periods to pump water into a reservoir, and releases water to a lower reservoir to generate electricity during peak power load periods. It can convert excess electricity during low grid load periods into high-value electricity during peak grid load periods. At present, the existing pumped storage unit seat ring volute split surface adopts a split surface transition plate + a joint (also called a compensation joint) structure. Referring to Figure 1 of the specification, the manufacturing process is as follows: the joint and the transition plate are cut and formed as one piece, the transition plate is separated, the transition plate is assembled and welded, the seat ring is assembled, the joint is prepared, and the joint is assembled and welded on site. During the manufacturing process, since the forming dimensions of the joint and the dimensions of the volute mouth adjacent to the joint have standard tolerances, the joint is prepared as a three-dimensional spatial curve. Therefore, the existing volute seat ring structure and production method have the following problems and difficulties:

[0003] (1) After the joint is formed, the transition plate needs to be separated. The transition plate is first welded to the seat ring and then to the joint. There are many processes and some invalid processes.

[0004] (2) When the joint is assembled, in order to ensure the dimensional accuracy of the inlet and outlet surfaces, the two end surfaces need to be processed, which takes a long time to process;

[0005] (3) It is difficult to prepare the joint in the factory. The gap and misalignment often exceed the tolerance. It is difficult to meet the 100% qualified size of the joint.

[0006] (4) The preparation is done twice, which takes up a long production cycle;

[0007] (5) The joint is difficult to assemble on site, the welding amount is large, the welding stress is large, the seat ring is greatly deformed after welding, and the on-site manufacturing cycle is long.

[0008] For example, the invention patent with publication number CN114473377A, publication date May 13, 2022, and invention name “A method for manufacturing a split-flap volute seat ring for a hydraulic turbine” includes the following steps: a. blanking the disc-shaped edge and the compensation section as a whole, then roll-forming the disc-shaped edge and the compensation section as a whole, and then cutting them into single pieces, with adjacent disc-shaped edges forming a single piece; b. assembling and overlapping the two volute seat ring petals, and then assembling and welding the disc-shaped edges at the split-flap surface of the volute seat ring as a whole; c. pre-assembling the compensation section at the split-flap surface of the volute seat ring to complete the manufacture of the volute seat ring. The present invention can avoid the problem of excessive misalignment during the pre-assembly and assembly of the compensation section and the disc-shaped edge of the split-flap volute seat ring of a large hydraulic turbine, ensure the stability of the manufacturing quality, simplify the manufacturing process, and effectively improve the manufacturing efficiency.

[0009] Although the above-mentioned prior art proposes a new method for manufacturing a volute seat ring, the volute seat ring in this patent still adopts the traditional structural form of a matching section and a transition plate. Therefore, there are still problems and defects such as difficulty in configuring the matching section, difficulty in ensuring the quality of the volute seat ring, and a long overall manufacturing cycle.

[0010] Summary of the Invention

[0011] In order to solve the problems and deficiencies in the above-mentioned prior art, the present invention proposes a method for manufacturing a seat ring volute for a pumped storage unit. This solution sets two left and right volute petals along the seat ring volute petal surface, eliminates the petal surface transition plate + makeshift joint structure, and the two volute petals are cut and formed as a whole. They are then 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 after being rounded at the construction site, they are welded and assembled. 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 dimensional accuracy and welding quality of the seat ring volute and shorten the manufacturing cycle.

[0012] In order to achieve the above-mentioned object of the invention, the technical solution of the present invention is as follows:

[0013] A method for manufacturing a seat ring volute of a pumped storage unit, wherein the seat ring volute is divided into two petals at 180 degrees for assembly and welding to meet transportation requirements, specifically comprising the following steps:

[0014] Step S1. Cut the volute segment as a whole, wherein a pre-set cutting margin is provided for the volute segment located at the volute surface;

[0015] Step S2. Assemble the volute segments other than the split volute segment onto the two split seat ring blanks, align and level the two split seat ring blanks with the volute segments, and then assemble the split volute segments onto the leveled structure to form a complete split seat ring blank. The split seat ring blank is then split into two split seat ring blanks, and each of the two split seat ring blanks is annealed.

[0016] Step S3. Processing the assembly surface of the seat ring and volute split blank with a flat edge and a bevel edge to finally form the seat ring and volute split;

[0017] Step S4. The two seat ring volute petals are transported to the construction site, the two seat ring volute petals are assembled into a circle on the construction site, and finally the two seat ring volute petals are welded along the assembly surfaces of the two seat ring volute petals to form a whole, thereby completing the manufacture of the seat ring volute.

[0018] Preferably, in step S1, integral blanking refers to integrally blanking and forming the volute segment through a CNC machine tool.

[0019] Preferably, step S2 specifically includes the following contents:

[0020] Step S2.1. Assemble and weld the upper and lower ring plates to the fixed guide vanes to obtain a split seat ring blank. Machining the assembly surfaces of the split seat ring blank is performed, leaving machining allowances on the assembly surfaces at both ends of the split seat ring blank.

[0021] Step S2.2. Draw the centerline of the water guide mechanism of the split seat ring blank. Use the intersection of the theoretical assembly surface of the split seat ring blank and the plane of the upper or lower plane of the split seat ring blank as the X-axis. Draw the Y-axis perpendicular to the X-axis. Use the water guide mechanism centerline, the X-axis, and the Y-axis as the assembly reference lines for the split seat ring blank.

[0022] Step S2.3. Assemble all volute segments except the volute segment onto the two seat ring split blanks according to the assembly reference line of the seat ring split blank and weld them to form two first-stage seat ring and volute split blanks;

[0023] Step S2.4. Redraw the centerline of the water guide mechanism and the X and Y axes of the seat ring split blank in the same manner as in step S2.2;

[0024] Step S2.5. Assemble and level the two first-stage seat ring volute split blanks according to the redrawn water guide mechanism centerline, X-axis, and Y-axis from Step S2.4. Add a spacer between the assembly surfaces of the two seat ring split blanks. The two first-stage seat ring volute split blanks now form the first-stage seat ring volute blank.

[0025] Step S2.6. Assemble the split volute segment on the first-stage seat ring volute blank to form the second-stage seat ring volute blank, and weld an anti-deformation support on the inner circle side of the split volute segment 150 mm away from the assembly surface of the seat ring split volute blank;

[0026] Step S2.7. Complete the welding of half the single-sided groove of all horizontal, horizontal, and vertical weld positions of the split-petal volute segment. Split the second-stage seat ring volute blank into two petals along the cutting line on the split-petal volute segment, forming two second-stage seat ring volute split-petal blanks. The cut surface formed after cutting and the assembly surface of the seat ring split-petal blank together constitute the assembly surface of the second-stage seat ring volute split-petal blank.

[0027] Step S2.8. Turn over the single second-stage seat ring volute split blank and complete all welding of the blank's flat, horizontal, and vertical welding positions, root cleaning, and grooves.

[0028] Step S2.9. Continue turning over the single second-stage seat ring volute split blank and complete the remaining welding of the weld groove in step S2.7.

[0029] Step S2.10. Check the dimensions of the single second-stage seat ring volute split blank, and anneal it after it passes the test.

[0030] Preferably, during annealing, support is added below the mouth surface of the seat ring volute split blank, and the elevation of the center of the mouth surface of the seat ring volute split blank is adjusted so that the elevation difference with the center line of the water guide mechanism is ≤3mm and the two petals are in the same direction.

[0031] Preferably, the anti-deformation support is in a cross shape.

[0032] Preferably, the cutting line and the line connecting the center points of the two pads are located in the same plane.

[0033] Preferably, in step S3, processing the assembly surface of the seat ring volute split blank into a flat surface and a bevel means processing the cutting surface and the assembly surface of the seat ring split blank into a flat surface and a bevel together.

[0034] Preferably, after the first-stage seat ring volute petal blanks are assembled and leveled, the horizontality deviation of the two blanks is ≤0.5mm, the X-axis parallelism of the two blanks is ≤0.5mm, and the Y-axis coaxiality is ≤0.5mm.

[0035] Beneficial effects of the present invention:

[0036] (1) The present invention optimizes the structure of the traditional split-flap transition plate + fitting joint into a volute split-flap structure, and adopts a method of integrated blanking, forming, welding, cutting and processing of the volute split, which can completely solve the quality risks of the existing pumped storage unit seat ring volute structure fitting joint assembly gap and misaligned tooth size, reduce the assembly difficulty of the seat ring volute, reduce the welding amount, and improve the quality reliability of the seat ring volute manufacturing; at the same time, it reduces the workload of actual matching, assembly and welding in the factory and on the construction site, and shortens the manufacturing cycle.

[0037] (2) The volute of the present invention is cut, formed, and welded in one piece, and then cut and processed along the petal surface, which improves the consistency of the radius size of the volute petal surface. Through UG simulation calculation, the amount of tooth misalignment of the volute on the petal surface is about 1 mm, which greatly improves the assembly dimensional accuracy.

[0038] (3) When the volute of the present invention is cut, a processing allowance is reserved for the cutting surface of the volute petals, and the allowance is removed together with the assembly surface of the seat ring at a later stage. Therefore, the circumferential dimensional accuracy of the volute petal surface is greatly improved, and the gap between the volute petals can be controlled within 1 mm.

[0039] (4) Under the condition that the weld performance and flaw detection requirements are the same, the present invention reduces the number of welds and the amount of welding of the seat ring volute at the construction site, reduces the welding stress, and improves the dimensional accuracy of the seat ring volute after on-site assembly welding.

[0040] (5) The present invention transfers the existing seat ring volute structure's relatively large stress-bearing petal surface transition plate + joint longitudinal seam from on-site welding to factory welding and annealing, thereby improving weld quality.

[0041] (6) The present invention reduces the steps of dividing the transition plate, assembling the seat ring and preparing the pre-installation process in the factory, and also reduces the workload of assembling and welding the joint on site, thereby greatly shortening the manufacturing cycle and improving the production efficiency of the enterprise. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The foregoing and following detailed description of the present invention will become more apparent when read in conjunction with the following drawings, in which:

[0043] FIG1 is a schematic diagram of the three-dimensional structure of the seat ring and volute of an existing pumped storage unit in the background art;

[0044] FIG2 is a schematic plan view of a seat ring volute of an existing pumped storage unit in the background art;

[0045] FIG3 is a schematic diagram of welding the seat ring and volute of a conventional pumped storage unit in the background art;

[0046] FIG4 is a schematic diagram of the three-dimensional structure of the seat ring volute of the pumped storage unit according to the present invention;

[0047] FIG5 is a schematic plan view of a seat ring volute of a pumped storage unit according to the present invention;

[0048] FIG6 is a schematic diagram of the welding of the seat ring and volute of the pumped storage unit according to the present invention. DETAILED DESCRIPTION

[0049] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the following will further illustrate the technical solutions for achieving the purpose of the present invention through several specific embodiments. It should be noted that the technical solutions claimed for protection by the present invention include but are not limited to the following embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making any creative efforts shall fall within the scope of protection of the present invention.

[0050] The volute of the existing pumped storage unit adopts a structure of a split-flap transition plate + a compensating section (also called a compensation section). Its structure can be seen in Figures 1 to 3 of the specification. The main purposes of this structural design are twofold: one is to solve the problem of split-flap transportation of the seat ring volute, and the other is to solve the accumulation of circumferential dimensional deviations after assembly and welding of multiple-section volutes. Its manufacturing process is roughly as follows: (1) The compensating section and the transition plate are cut and formed into a C-shaped section; (2) The transition plate is cut out; (3) The seat ring is leveled and rounded; (4) The transition plate is assembled and welded; (5) The compensating section is roughly prepared; (6) The transition plate is cut along the split-flap surface; (7) The seat ring is processed; (8) The seat ring is rounded; (9) The compensating section is finely prepared; (10) The compensating section is assembled and welded on site.

[0051] During the manufacturing process, due to the standard tolerances of the forming dimensions of the joint and the dimensions of the volute opening adjacent to the joint, and the fact that the joint is a three-dimensional curve, the joint is difficult to precisely manufacture, the quality is difficult to guarantee, and the manufacturing cycle is long. Therefore, the manufacturing difficulties of the existing volute seat ring structure are summarized as follows:

[0052] (1) After the joint is formed, the transition plate needs to be separated. The transition plate is first welded to the seat ring and then to the joint. There are many processes and some invalid processes.

[0053] (2) When the joint is assembled, in order to ensure the dimensional accuracy of the inlet and outlet surfaces, the two end surfaces need to be processed, which takes a long time to process;

[0054] (3) It is difficult to prepare the joint in the factory. The gap and misalignment often exceed the tolerance. It is difficult to meet the 100% qualified size of the joint.

[0055] (4) The preparation is done twice, which takes up a long production cycle;

[0056] (5) The joint is difficult to assemble on site, the welding amount is large, the welding stress is large, the seat ring is greatly deformed after welding, and the on-site manufacturing cycle is long.

[0057] Based on this, this embodiment provides a method and structure for manufacturing a seat ring volute of a pumped storage unit. This solution sets two left and right volute petals along the seat ring volute petal surface, cancels the petal surface transition plate + make-up section structure, and the two volute petals are cut and formed as one, and then welded and annealed in the factory, and then cut along the petal surface. The distinguishing 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 welded and assembled after being rounded at the construction site. The entire seat ring volute structure only has a circumferential weld on the assembly surface.

[0058] In this embodiment, it should be noted that the seat ring and volute are a combination structure of a seat ring and a volute, wherein;

[0059] The volute as a whole is a spiral tubular structure, having a head end and a tail end, which intersect, but the head end and the tail end of the volute are connected and not communicated; further, the volute is assembled and welded by a number of C-shaped volute sections, among which the volute section located at the resolution surface is called a petal volute section in this embodiment.

[0060] The seat ring is formed by two 180-degree seat ring petals spliced ​​together. The seat ring is fixedly connected to the volute arranged above it by welding, and the head and tail ends of the seat ring are overlapped with the head and tail ends of the volute. An opening is provided on the inner circumference of the volute for installing the seat ring. The seat ring as a whole extends along the inner circumference of the volute and is welded in the opening. Furthermore, a single seat ring is composed of two upper and lower ring plates arranged parallel to each other, and fixed guide vanes located between the two ring plates. A plurality of fixed guide vanes are distributed at equal intervals along the circumference of the volute starting from the head end of the volute, which can achieve the effect of uniform water supply; furthermore, the fixed guide vanes are inclined at a certain angle along the direction of water flow, which can buffer the impact force of the water flow to a certain extent.

[0061] An embodiment of the present invention discloses a method for manufacturing a seat ring volute for a pumped storage unit. To meet transportation requirements, the seat ring volute is first manufactured and formed into two 180-degree petal structures in a factory. The two 180-degree petal structures are then transported to the construction site, where they are assembled and welded together to form a complete spiral seat ring volute. The structure and welding method of the entire seat ring volute can be seen in Figures 4 to 6 of the specification. This method specifically includes the following steps:

[0062] Step S1. All volute segments required for assembly are integrally blanked and formed by a CNC machine tool to form a number of volute segments with a C-shaped structure, wherein the two split volute segments located at the split surface of the seat ring volute are preset with cutting allowances during blanking and forming.

[0063] In this embodiment, the cutting margin is generally 30 mm.

[0064] Step S2. In the processing factory, all volute sections except the split volute sections are respectively assembled on two seat ring split blanks, and then the two seat ring split blanks assembled with volute sections are assembled and leveled, and then the split volute sections are assembled on the structure after the assembly and leveling, and the two seat ring split blanks are assembled to form a seat ring blank, and all volute sections arranged on the seat ring blank constitute the volute blank, and finally the seat ring blank and the volute blank form a complete seat ring volute blank, and finally the seat ring volute blank is divided into two seat ring volute split blanks, and the two seat ring volute split blanks are annealed respectively.

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

[0066] Step S2.1. Assembly of the seat ring petal plate and the fixed guide vane and rough processing of the assembly surface: The upper ring plate and the lower ring plate of the seat ring petal structure are welded to the fixed guide vane by welding equipment. After welding, the corresponding seat ring petal blank is obtained, and then the assembly surface of the seat ring petal blank is processed, and a subsequent processing allowance of 7mm is left on the assembly surfaces at both ends.

[0067] In this embodiment, it should be noted that, since the seat ring of the seat ring volute is formed by splicing two seat ring petals, two seat ring petal blanks will be obtained during processing.

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

[0069] Step S2.2. Draw the centerline of the water guide mechanism of a single split seat ring blank. Use the intersection of the theoretical assembly surface of the split seat ring blank and the plane of the upper or lower plane of the split seat ring blank as the X-axis. Draw the Y-axis perpendicular to the X-axis. Use the water guide mechanism centerline, the X-axis, and the Y-axis as the assembly reference lines for the split seat ring blank.

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

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

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

[0073] Step S2.3. According to the assembly reference line of the seat ring split blank drawn in step S2.2, all volute segments except the split volute segment are assembled onto the two seat ring split blanks respectively to form two first-stage seat 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 seat ring split blank in the same manner as in step S2.2, and use them as the new assembly reference line.

[0075] Step S2.5. According to the marking results of step S2.4, and based on the principle that the center lines of the two-petal water-guiding mechanisms are in the same plane and the horizontality deviation is ≤0.5mm, the X-axis parallelism is ≤0.5mm, and the Y-axis coaxiality is ≤0.5mm, the two first-stage seat ring volute petal blanks are leveled and rounded, and a spacer is added between the assembly surfaces of the two first-stage seat ring volute petal blanks. After the two first-stage seat ring volute petal blanks are adjusted and rounded, they constitute the first-stage seat ring volute blank.

[0076] In this embodiment, it should be noted that the pad structure added between the two blanks is actually installed between the two seat ring petal blanks, located at the assembly surfaces of the two seat ring petals. A single seat ring petal blank has two assembly surfaces. Therefore, after the two seat ring petal blanks are leveled and assembled into a circle, there are two pads in total; after the adjustment and assembly, the pads do not have a connection relationship with the assembly surfaces of the seat ring petal blanks on both sides, but are only stuck between the two assembly surfaces. The entire seat ring petal blank is free and without any constraints.

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

[0078] Step S2.6. Assemble the split volute segments on the first-stage seat ring volute blank. At this time, the volute segments on the entire seat ring blank are installed in place. All the volute segments constitute the volute blank on the seat ring blank. The volute blank and the seat ring blank below together constitute the second-stage seat ring volute blank. Anti-deformation supports are welded on the inner circle side of the split volute segment 150 mm away from the assembly surface of the seat ring split blank.

[0079] In this embodiment, it should be noted that, after the assembly in step 2.6, the second-stage seat ring volute blank formed is the final complete seat ring volute blank structure, and the final assembly welding, cutting and polishing are carried out on its basis to obtain two seat ring volute petal structures.

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

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

[0082] In this embodiment, it should be noted that the cutting line and the line connecting the center points of the two pads at the seat ring assembly surface are located in the same plane.

[0083] In this embodiment, it should also be noted that the cutting process is essentially to cut the split volute located at the resolution surface into two lobes. Since the two seat ring blanks below are not connected together at this time, in this embodiment, the assembly surface of the second-stage seat ring volute split blank is equivalent to the resolution surface blank of the later seat ring volute structure. The assembly surface needs to be processed subsequently before the final resolution surface can be obtained.

[0084] Step S2.8. Turn over the single second-stage seat ring volute petal blank and complete all welding of the weld root cleaning surface grooves in all horizontal, horizontal and vertical welding positions of the blank.

[0085] In this embodiment, turning over refers to flipping the structure 180 degrees.

[0086] Step S2.9. Continue turning over the single second-stage seat ring volute split blank and complete the remaining welding of the weld groove in step S2.7.

[0087] Step S2.10. Check the dimensions of the single second-stage seat ring volute split blank, and anneal it after it passes the test.

[0088] In this embodiment, it should be noted that during annealing, support is added below the mouth surface of the seat ring volute petal, and the elevation of the center of the mouth surface of the seat ring volute petal blank is adjusted so that the elevation difference with the center line of the water guide mechanism is ≤3mm and the two petals are in the same direction.

[0089] In this embodiment, it should also be noted that, whether the petaled volute segment located at the resolution surface position or the remaining volute segments are assembled to the seat ring, there is assembly welding between the volute segment and the adjacent volute segment, as well as assembly welding between the volute segment and the seat ring below. After the welding is completed, a whole is finally formed.

[0090] Step S3: respectively process the assembly surfaces of the two seat ring volute split blanks into flat edges and bevel edges, and finally form the seat ring volute splits.

[0091] In this embodiment, processing the assembly surface of the seat ring volute petal blank into a flat edge and a bevel means processing the cutting surface of the volute together with the assembly surface of the seat ring petal blank into a flat edge and a bevel, and the seat ring volute petal is obtained after processing. The processed surface is the assembly surface of the seat ring volute petal, which is also the distinguishing surface of the entire seat ring volute structure.

[0092] In this embodiment, steps S2 and S3 represent the entire process of manufacturing the seat ring and volute segments. Both steps are completed within the manufacturing facility. The resulting seat ring and volute segments are then transported to the construction site for assembly. This assembly, step S4 of this solution, is described below.

[0093] Step S4. The two seat ring volute petals are transported to the construction site, the two seat ring volute petals are assembled into a circle on the construction site, and finally the two seat ring volute petals are welded along the assembly surfaces of the two seat ring volute petals to form a whole, thereby completing the manufacture of the seat ring volute.

[0094] The seat ring volute structure manufactured using the above scheme eliminates the structure of the petal surface transition plate and the joint. The two volute petals are cut and formed in one piece, then welded and annealed in the factory. They are then cut along the petal surface. The resolution surface of the volute petals is processed together with the assembly surface of the seat ring, ultimately forming two seat ring volute petals. The two seat ring volute petals are transported to the construction site, where they are rounded and assembled by welding. The entire seat ring volute structure only has a circumferential weld on the assembly surface. Therefore, the manufacturing method of the present invention can improve the assembly dimensional accuracy and welding quality of the seat ring volute, and shorten the manufacturing cycle.

[0095] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification or equivalent change made to the above embodiment based on the technical essence of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A method for manufacturing a seat ring volute of a pumped storage unit, wherein the seat ring volute is divided into two petals at 180° for assembly and welding to meet transportation requirements, characterized in that: The following steps are involved: Step S1. Cut the volute segment as a whole, wherein the split volute segment located at the split surface has a preset cutting margin; Step S2. assemble the volute segments other than the split-petal volute segment on the two seat ring split-petal blanks respectively, assemble and level the two seat ring split-petal blanks equipped with the volute segments, and then assemble the split-petal volute segment on the structure after the assembling and leveling, finally forming a complete seat ring volute blank, and then divide the seat ring volute blank into two seat ring volute split-petal blanks, and anneal the two seat ring volute split-petal blanks respectively; Step S3. Processing the assembly surface of the seat ring volute split blank with a flat edge and a groove to finally form the seat ring volute split; Step S4. transport the two seat ring volute petals to the construction site, assemble the two seat ring volute petals into a circle on the construction site, and finally weld the two seat ring volute petals along the assembly surfaces of the two seat ring volute petals to form a whole, thereby completing the manufacture of the seat ring volute.

2. A method for manufacturing a seat ring volute of a pumped storage unit according to claim 1, characterized in that: In step S1, integral blanking refers to integrally blanking and forming the volute segment through a CNC machine tool.

3. A method for manufacturing a seat ring volute of a pumped storage unit according to claim 1, characterized in that: The step S2 specifically includes the following contents: Step S2.

1. Assemble and weld the upper and lower ring plates and the fixed guide vanes to obtain a seat ring split blank, and then process the assembly surface of the seat ring split blank. The assembly surfaces at both ends of the seat ring split blank are left with machining allowances; Step S2.

2. Draw the center line of the water guide mechanism of the seat ring split-petal blank, take the intersection line of the theoretical assembly surface of the seat ring split-petal blank and the plane where the upper plane or the lower plane of the seat ring split-petal blank is located as the X-axis, draw the Y-axis perpendicular to the X-axis, and take the center line of the water guide mechanism, the X-axis and the Y-axis as the assembly reference line of the seat ring split-petal blank; Step S2.

3. According to the assembly reference line of the seat ring split blank, all volute segments except the split volute segment are assembled to two seat ring split blanks and welded to form two first-stage seat ring volute split blanks; Step S2.

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

5. According to the center line of the water guide mechanism, the X-axis and the Y-axis redrawn in step S2.4, the two first-stage seat ring volute petal blanks are assembled and leveled, and a cushion block is arranged between the assembly surfaces of the two seat ring petal blanks. At this time, the two first-stage seat ring volute petal blanks after being assembled constitute the first-stage seat ring volute blank; Step S2.

6. Assemble the split volute segment on the first-stage seat ring volute blank to form the second-stage seat ring volute blank, and weld an anti-deformation support on the inner circle side of the split volute segment; Step S2.

7. Complete the welding of half of the single-sided groove of all horizontal, horizontal and vertical welding positions of the split volute section, and split the second-stage seat ring volute blank into two petals along the cutting line to form two second-stage seat ring volute split blanks. Together with the assembly surface of the seat ring split blank, it forms the assembly surface of the second-stage seat ring volute split blank; Step S2.

8. Turn over the single second-stage seat ring volute split blank and complete all welding of the weld root cleaning surface grooves at all flat, horizontal and vertical welding positions of the blank; Step S2.

9. The single second-stage seat ring volute split blank continues to turn over and completes the remaining welding of the weld groove in step S2.7; Step S2.

10. Check the size of the single second-stage seat ring volute split blank, and anneal it after it passes the test.

4. A method for manufacturing a seat ring volute of a pumped storage unit according to claim 1, characterized in that: During annealing, add support below the mouth surface of the seat ring volute split blank, adjust the elevation of the center of the mouth surface of the seat ring volute split blank, and make the elevation difference with the center line of the water guide mechanism ≤3mm and the two petals have the same deflection.

5. A method for manufacturing a seat ring volute of a pumped storage unit according to claim 3, characterized in that: The anti-deformation support is in a cross shape.

6. A method for manufacturing a seat ring volute of a pumped storage unit according to claim 3, characterized in that: The cutting line and the line connecting the center points of the two pads are located in the same plane.

7. A method for manufacturing a seat ring volute of a pumped storage unit according to claim 3, characterized in that: In the step S2.6, an anti-deformation support is welded on the inner circle side of the split-petal volute segment at a distance of 150 mm from the assembly surface of the seat ring split-petal blank.

8. A method for manufacturing a seat ring volute of a pumped storage unit according to claim 1, characterized in that: In the step S3, processing the assembly surface of the seat ring volute split blank into a flat surface and a beveled surface means processing the cutting surface and the assembly surface of the seat ring split blank into a flat surface and a beveled surface together.

9. A method for manufacturing a seat ring volute of a pumped storage unit according to claim 3, characterized in that: After the first stage seat ring volute petal blanks are assembled and leveled, the horizontality deviation of the two blanks is ≤0.5mm, the X-axis parallelism of the two blanks is ≤0.5mm, and the Y-axis coaxiality is ≤0.5mm.

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