A turbine nozzle ring snap ring mounting structure

Abstract

This invention relates to the field of steam turbine units, specifically to a steam turbine nozzle ring clamping ring installation structure, including a nozzle outer ring. A slanted groove is formed on the top of the upper surface of the nozzle outer ring. A retaining ring is movably fitted inside the slanted groove on the surface of the nozzle outer ring. An annular groove is formed in the middle of the upper surface of the retaining ring. A contact surface A is provided on one side of the retaining ring near the annular groove, and a contact surface B is provided on the other side of the retaining ring near the annular groove. Through the radial positioning of the nozzle outer ring and the cylinder annular groove, and the three-point support of the double contact surfaces of the retaining ring, the overall coaxiality of the nozzle ring is ensured, preventing damage to the dynamic-static clearance due to radial movement, ensuring steam flow efficiency, and improving the steam turbine's work capacity. Furthermore, the elastic compensation design of the spliced ​​clamping band can evenly distribute circumferential pressure, and its axial contact surface with the top of the nozzle outer ring can effectively counteract the upward thrust of steam impact, reducing localized wear of components and extending the service life of the nozzle ring and related components.

Description

Technical Field

[0001] This invention relates to the field of steam turbine units, and more specifically to a steam turbine nozzle ring retaining ring installation structure. Background Technology

[0002] In the field of steam turbines, steam turbines are rotary power machines that convert steam energy into mechanical work. They are widely used in industries such as power and chemical engineering. As a core component of the steam turbine's flow passage, the nozzle ring's function is to convert the pressure energy of steam into kinetic energy, forming a high-speed steam flow that impacts the moving blades to do work. Therefore, the stability of its axial position is crucial to the steam turbine's flow efficiency and operational reliability. To prevent the nozzle ring from axially shifting under the impact and vibration of the steam flow, it is necessary to use retaining rings to position it axially.

[0003] During the steam flow and work process in a steam turbine, the nozzle, as the core component for steam energy conversion, directly affects the sealing performance and efficiency of the unit, as well as its long-term stable operation, through its connection structure with the cylinder. Therefore, it is an important technical design aspect of the steam turbine.

[0004] The nozzle is the first stationary component inside the steam turbine that converts the internal energy of high-temperature, high-pressure steam into the kinetic energy of the rotor. Typically, the nozzle is welded to the inner and outer rings, then welded to the outer and inner rings. The resulting arc-shaped section of multiple nozzles is then installed as a whole into an annular groove on the inner wall of the cylinder. This directly welded nozzle ring installation structure is widely used in steam turbine structures and is usually connected to the cylinder using multiple bolts. However, steam turbines operate under high-temperature, high-pressure conditions for extended periods. The threaded hole area, as a stress concentration point, is prone to microcracks due to material creep accumulation. If these cracks continue to expand, they may lead to cylinder sealing failure and even steam leakage, posing safety hazards. Furthermore, the high-temperature steam environment easily causes oxidation and corrosion on the bolt and threaded hole surfaces, gradually reducing the fit precision. In addition, the thermal expansion and contraction differences caused by sudden temperature changes during unit start-up and shutdown can easily lead to bolt loosening. Summary of the Invention

[0005] This invention addresses the technical problems existing in the prior art by providing a turbine nozzle ring retaining ring installation structure.

[0006] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: A turbine nozzle ring clamping ring installation structure includes a nozzle outer ring, a slanted groove is formed on the top of the upper surface of the nozzle outer ring, a retaining ring is movably sleeved inside the slanted groove on the surface of the nozzle outer ring, an annular groove is formed in the middle of the upper surface of the retaining ring, a contact surface A is provided on one side of the retaining ring near the annular groove, a contact surface B is provided on the other side of the retaining ring near the annular groove, a chamfer is provided on one side of the contact surface A of the retaining ring, the contact surface A of the retaining ring is in contact with the nozzle outer ring, a cylinder is sleeved on the outer arc surface of the nozzle outer ring, the contact surface B of the retaining ring abuts against the inner side of the cylinder, a clamping band is connected and sleeved in the annular groove on the surface of the retaining ring, the clamping band is located between the nozzle outer ring and the cylinder, an annular clamping body is abutted at the top of the retaining ring, and the lower surface of the clamping band is placed on the top of the nozzle outer ring.

[0007] A gap is provided between one end of the retaining ring and the cylinder, and an inner folded end is provided in the middle of the inner arc surface of the annular clip body, which abuts against the surface of the pressing band.

[0008] An inner groove is provided between the inner folded end and the top of the annular card body, and one side of the protective ring abuts against the inner groove between the inner folded end and the annular card body.

[0009] The outer arc surface of the annular card body is provided with a U-shaped side ring, and a hinge part is provided between the U-shaped side ring and the annular card body. A through groove is provided on the upper surface of the hinge part.

[0010] The bottom end of the U-shaped side ring is set as a raised edge, and the guide ring body is connected through the groove on the surface of the hinge part.

[0011] The top of the guide ring body is provided with a bent arc end, the top of the bent arc end extends through the groove surface, and the inner arc surface abuts against the top of the U-shaped side ring.

[0012] The guide ring body has a vertical reference surface near the bent arc end, the lower end of the vertical reference surface has an arc segment, and the bottom end of the arc segment has a flexible raised edge.

[0013] The bottom end of the flexible edge is inserted between the inner arc surface of the annular card and the outer ring of the nozzle. The vertical reference surface and the arc segment are attached to the surface of the pressure band. The annular card and the guide ring body are interlocked.

[0014] The compression band is made of multiple arc-shaped bands spliced ​​together end to end. The inner arc surface of the compression band has a recessed groove in the middle, and the recessed groove of the inner arc surface of the compression band is adapted to the surface of the annular groove.

[0015] The beneficial effects of this invention are: The radial positioning of the nozzle outer ring and the cylinder annular groove, along with the three-point support of the double contact surface of the retaining ring, ensures the overall coaxiality of the nozzle ring, preventing damage to the dynamic and static clearance due to radial movement, ensuring steam flow efficiency, and improving the turbine's work capacity. Furthermore, the elastic compensation design of the spliced ​​clamping band can evenly distribute circumferential pressure, and its axial contact surface with the top of the nozzle outer ring can effectively counteract the upward thrust of steam impact, reduce local wear of components, and extend the service life of the nozzle ring and related components.

[0016] The reserved gap between the retaining ring and the cylinder can accommodate the radial expansion difference at high temperatures, preventing parts from jamming or deforming, and ensuring the adaptability of the unit under high-parameter operating conditions. The circumferential telescopic design of the clamping belt and the oblique sliding structure of the double contact surface of the retaining ring can simultaneously absorb the thermal deformation of the outer ring of the nozzle, disperse and release the shear stress generated by thermal expansion and contraction, avoid the problem of residual stress accumulation in traditional welded structures, and extend the fatigue life of core components.

[0017] By adopting a mechanical interlocking structure that uses a ring-shaped wedge clamp and a secondary locking mechanism with the guide ring body to replace the traditional bolt connection, the risk of thread loosening and seizing is completely eliminated. It can maintain a stable locking force even under high temperature and vibration conditions, which greatly improves the reliability of unit operation. The elastic compensation and hinge design of the U-shaped side ring can adapt to the stress changes caused by guide ring installation errors and temperature cycles, avoid stress concentration and component damage caused by rigid connection, and further enhance the long-term stability of the structure. Attached Figure Description

[0018] Figure 1 This is a structural diagram illustrating the connection between the nozzle outer ring and the cylinder of the present invention; Figure 2 This is a schematic diagram of the connection structure between the retaining ring and the clamping band of the present invention; Figure 3 This is a structural diagram of the upper and lower parts of the ring-shaped card body of the present invention; Figure 4 This is a schematic diagram of the ring-shaped card body structure of the present invention; Figure 5 This is a schematic diagram of the structure of the guide ring body of the present invention; Figure 6 A schematic diagram of the surface structure of the guide ring body in this invention.

[0019] 1. Nozzle outer ring; 101. Inclined groove; 2. Retaining ring; 201. Contact surface A; 202. Contact surface B; 203. Annular groove; 3. Cylinder; 4. Pressing band; 401. Recessed groove; 5. Ring-shaped clamp body; 501. Inward fold end; 502. U-shaped side ring; 503. Hinge part; 504. Through groove; 6. Guide ring body; 601. Bending arc end; 602. Vertical reference plane; 603. Arc segment type; 604. Soft edge; 7. Seams. Detailed Implementation

[0020] The present invention will now be further described with reference to the accompanying drawings.

[0021] like Figure 1 and Figure 2 As shown, this embodiment of the invention includes a nozzle outer ring 1. A slanted groove 101 is formed on the top of the upper surface of the nozzle outer ring 1. A retaining ring 2 is movably fitted inside the slanted groove 101 on the surface of the nozzle outer ring 1. An annular groove 203 is formed in the middle of the upper surface of the retaining ring 2. A contact surface A201 is provided on one side of the retaining ring 2 near the annular groove 203, and a contact surface B202 is provided on the other side of the retaining ring 2 near the annular groove 203. One side of the contact surface A201 of the retaining ring 2 has a chamfered right angle. One side of the contact surface A201 of the retaining ring 2 fits against the nozzle outer ring 1. A cylinder 3 is fitted onto the outer arc surface of the nozzle outer ring 1. The contact surface B202 on the other side of the retaining ring 2 abuts against the inner side of the cylinder 3. The annular groove 203 on the surface of the retaining ring 2 connects to... A clamping band 4 is connected to the annular sleeve. The clamping band 4 is located between the outer ring 1 of the nozzle and the cylinder 3. The top of the guard ring 2 abuts against the annular clamp body 5. The lower surface of the clamping band 4 is placed on the top of the outer ring 1 of the nozzle. A gap 7 is provided between one end of the guard ring 2 and the cylinder 3. The inner arc surface of the annular clamp body 5 is provided with an inner folded end 501. The inner folded end 501 abuts against the surface of the clamping band 4. An inner groove is provided between the inner folded end 501 and the top of the annular clamp body 5. One side of the guard ring 2 abuts against the inner groove between the inner folded end 501 and the annular clamp body 5. The outer arc surface of the annular clamp body 5 is provided with a U-shaped side ring 502. A hinge part 503 is provided between the U-shaped side ring 502 and the annular clamp body 5. A through groove 504 is opened on the upper surface of the hinge part 503.

[0022] The outer arc surface of the nozzle outer ring 1 mates with the annular groove on the inner wall of the cylinder 3 to achieve initial radial positioning and ensure the coaxiality of the nozzle ring as a whole. The retaining ring 2 is sleeved with the top of the nozzle outer ring 1 through the inner inclined groove 101. The chamfered right angle design of the contact surface A201 not only eliminates stress concentration during assembly, but also provides an axial limiting basis for the nozzle outer ring 1 through surface contact. At the same time, the contact surface B202 is tightly connected to the inner side of the cylinder 3, forming a three-point support structure from the outer ring to the retaining ring 2 and then to the cylinder 3, which initially restricts radial movement. The pressing band 4, which is spliced ​​from multiple arc-shaped bands, achieves circumferential positioning and fit by matching the inner arc surface recessed groove 401 with the annular groove 203 of the retaining ring 2. The spliced ​​structure gives the pressing band 4 elastic compensation capability. By adjusting the fit of a single band segment, the circumferential pressure on the retaining ring 2 can be evenly distributed. At the same time, its lower surface fits with the top of the nozzle outer ring 1 to form an axial support surface, which counteracts the upward thrust generated by steam impact.

[0023] The annular clamping body 5 is engaged with the top of the retaining ring 2 through the inner groove, and the inner folded end 501 is perpendicular to the upper surface of the pressure band 4. By utilizing the triangular force-bearing structure of the retaining ring 2, the pressure band 4 and the annular clamping body 5, the radial preload of the pressure band 4 is converted into axial constraint force, thereby achieving axial locking of the nozzle outer ring 1. Mechanical engagement replaces the traditional bolt connection, avoiding the risk of thread loosening.

[0024] Combination Figures 3 to 6 In the U-shaped side ring 502, the bottom end is set as a raised edge. A guide ring body 6 is connected through the groove 504 on the surface of the hinge part 503. The top end of the guide ring body 6 is provided with a bent arc end 601, the top end of which extends through the surface of the groove 504 and abuts against the top of the U-shaped side ring 502 with its inner arc surface. A vertical reference surface 602 is provided on the surface of the guide ring body 6 near the bent arc end 601. An arc segment 603 is provided at the lower end of the vertical reference surface 602. The bottom end is provided with a flexible raised edge 604. The bottom end of the flexible raised edge 604 is inserted between the inner arc surface of the annular clip 5 and the outer ring 1 of the nozzle. The vertical reference surface 602 and the arc segment 603 are attached to the surface of the pressing band 4. The annular clip 5 and the guide ring body 6 are interlocked. The pressing band 4 is made of multiple arc-shaped bands spliced ​​end to end. The inner arc surface of the pressing band 4 is provided with a recessed groove 401. The recessed groove 401 of the inner arc surface of the pressing band 4 is adapted to the surface of the annular groove 203.

[0025] After the guide ring body 6 passes through the through slot 504 of the annular clamp body 5, the bent arc end 601 abuts against the top of the U-shaped side ring 502. With the help of leverage, the vertical reference surface 602 and the arc segment 603 are tightly fitted to the clamping band 4. At the same time, the flexible raised edge 604 is inserted into the gap between the annular clamp body 5 and the outer ring 1 of the nozzle, forming a double limit in the radial and axial directions. The elastic deformation of the flexible raised edge 604 continuously provides pre-tightening force, which can offset the gap change even with long-term vibration and avoid locking failure. The U-shaped side ring 502 is flexibly connected to the annular clamp body 5 through the hinge part 503. Its bottom edge design can absorb the installation error of the guide ring body 6. During the temperature cycle of unit start-up and shutdown, it can also adapt to the change of locking force through its own elastic deformation to prevent stress accumulation caused by rigid connection.

[0026] The gap 7 between the retaining ring 2 and the cylinder 3 is reserved with thermal expansion space to accommodate the radial expansion difference between the two at high temperature, so as to avoid the parts getting stuck or deformed. The multi-segment splicing design of the clamping band 4 gives it circumferential expansion and contraction capability, which can be adjusted synchronously with the thermal deformation of the outer ring 1 of the nozzle. Combined with the curved surface contact of the arc segment 603, it can disperse the local concentrated stress into uniform surface stress. The double contact surface of the retaining ring 2 adopts an oblique fitting design, which can release the shear stress generated by thermal expansion and contraction through slight sliding, avoiding the problem of residual stress accumulation in traditional welded structures.

[0027] The mating surfaces of the clamping band 4 and the retaining ring 2, the surface contact surfaces of the retaining ring 2 and the nozzle outer ring 1 and the cylinder 3, and the contact surface of the flexible raised edge 604 and the nozzle outer ring 1 form a three-level sealing structure, which effectively prevents high-temperature steam from flowing into the mating surfaces and reduces the risk of oxidation and corrosion. Compared with traditional bolt connections, this structure completely eliminates the threaded hole on the cylinder 3 through snap-fit ​​assembly, avoiding creep cracks caused by the threaded hole as a stress concentration area. At the same time, it eliminates the electrochemical corrosion channel between the bolt and the threaded hole, reducing the need for rust removal and re-tightening during operation and maintenance.

[0028] During disassembly, simply remove the guide ring body 6 first, then separate the snap-fit ​​between the annular clip 5 and the retaining ring 2, and the clamping band 4 and the retaining ring 2 can be removed in sequence without cutting, welding or special tools.

Claims

1. A turbine nozzle ring snap ring mounting structure characterized by, The device includes a nozzle outer ring (1), on the top of the upper surface of the nozzle outer ring (1) having a slanted groove (101). A retaining ring (2) is movably fitted inside the slanted groove (101) on the surface of the nozzle outer ring (1). An annular groove (203) is formed in the middle of the upper surface of the retaining ring (2). A contact surface A (201) is provided on one side of the retaining ring (2) near the annular groove (203), and a contact surface B (202) is provided on the other side of the retaining ring (2) near the annular groove (203). A chamfer is provided on one side of the contact surface A (201) of the retaining ring (2). The contact surface A (201) on one side of the retaining ring (2) is in contact with the outer ring (1) of the nozzle. The outer arc surface of the outer ring (1) of the nozzle is fitted with a cylinder (3). The contact surface B (202) on the other side of the retaining ring (2) is in contact with the inner side of the cylinder (3). A clamping band (4) is connected in the annular groove (203) on the surface of the retaining ring (2). The clamping band (4) is located between the outer ring (1) of the nozzle and the cylinder (3). The top of the retaining ring (2) is in contact with an annular clip (5). The lower surface of the clamping band (4) is placed on the top of the outer ring (1) of the nozzle.

2. A turbine nozzle ring snap ring mounting structure according to claim 1, wherein One end of the retaining ring (2) is provided with a gap (7) between it and the cylinder (3). The inner arc surface of the ring-shaped clip (5) is provided with an inner folded end (501), which abuts against the surface of the pressing band (4).

3. A turbine nozzle ring snap ring mounting structure according to claim 2, wherein An inner groove is provided between the inner folded end (501) and the top of the ring-shaped card body (5), and one side of the protective ring (2) abuts against the inner groove between the inner folded end (501) and the ring-shaped card body (5).

4. A turbine nozzle ring snap ring mounting structure according to claim 3, wherein The outer arc surface of the ring-shaped card body (5) is provided with a U-shaped side ring (502), and a hinge part (503) is provided between the U-shaped side ring (502) and the ring-shaped card body (5). A through groove (504) is provided on the upper surface of the hinge part (503).

5. A turbine nozzle ring snap ring mounting structure according to claim 4, wherein The bottom end of the U-shaped side ring (502) is set as a raised edge, and the guide ring body (6) is connected through the groove (504) on the surface of the hinge part (503).

6. The turbine nozzle ring retaining ring installation structure according to claim 5, characterized in that, The top of the guide ring body (6) is provided with a bent arc end (601), the top of the bent arc end (601) extends through to the surface of the through groove (504), and the inner arc surface abuts against the top of the U-shaped side ring (502).

7. The turbine nozzle ring retaining ring installation structure according to claim 6, characterized in that, The guide ring body (6) has a vertical reference surface (602) on the surface near the bent arc end (601), the lower end of the vertical reference surface (602) has an arc segment (603), and the bottom end of the arc segment (603) has a soft-facing edge (604).

8. The turbine nozzle ring retaining ring installation structure according to claim 7, characterized in that, The bottom end of the flexible edge (604) is inserted between the inner arc surface of the annular card body (5) and the outer ring (1) of the nozzle. The vertical reference surface (602) and the arc segment (603) are attached to the surface of the pressing band (4). The annular card body (5) and the guide ring body (6) are interlocked.

9. The turbine nozzle ring retaining ring installation structure according to claim 8, characterized in that, The compression band (4) is made of multiple arc-shaped bands spliced ​​together end to end. The inner arc surface of the compression band (4) is provided with a recessed groove (401). The recessed groove (401) on the inner arc surface of the compression band (4) is adapted to the surface of the annular groove (203).

Images