Thermal power steam turbine last-stage blade and thermal power steam turbine using same

Abstract

The invention discloses a thermal power steam turbine last-stage blade and a thermal power steam turbine using the same, and relates to the field of steam turbine application, the thermal power steam turbine last-stage blade comprises a steam turbine, a wheel disc is arranged in the steam turbine, blades are movably installed on the side face of the wheel disc, and clamping grooves used for clamping the blades are formed in the side face of the wheel disc; mounting grooves used for mounting the blades are formed in the side face of the wheel disc, and a cover plate capable of pressing the blades is arranged on the side face of the wheel disc. The multiple sets of clamping grooves are formed in the wheel disc, the mounting grooves are formed in the side faces of each set of clamping grooves, accordingly, each set of blades can be independently mounted and dismounted when being mounted in the corresponding clamping groove, then a circle of blades mounted around the wheel disc are pressed through the circular ring cover plates, the circular ring cover plates are split into four sets, and therefore the blades can be conveniently mounted and dismounted; furthermore, the multiple groups of blades are also divided into four groups to be disassembled and assembled, so that the blades are relatively simple and easy to assemble, and the later replacement of the blades is more convenient.

Description

Technical Field

[0001] The invention relates to the application field of steam turbines, in particular to a last-stage blade of a thermal power steam turbine and a thermal power steam turbine using the blade. Background Art

[0002] A steam turbine, also known as a steam turbine engine, is a rotary steam power device. High-temperature and high-pressure steam passes through a fixed nozzle to become an accelerated airflow and is then sprayed onto the blades, causing the rotor with the blade rows to rotate and perform work externally. Steam turbines are the main equipment in modern thermal power plants and are also used in the metallurgical industry, chemical industry, and ship power plants.

[0003] A steam turbine is an external combustion rotary machine that can convert steam thermal energy into mechanical work. After the steam from the boiler enters the steam turbine, it passes through a series of annularly configured nozzles and moving blades in turn, converting the steam thermal energy into mechanical energy for the rotation of the turbine rotor. When the steam turbine unit is operating under a small volume flow condition (low load operation) during the peak regulation period, the last stage blades are prone to overheating, which will cause water spray cooling to be put into operation. Water spray cooling causes a large number of large water droplets to flow back from the root of the last stage outlet, and are sucked into the last stage channel to flush the blades, thereby causing water erosion of the blades. Severe blade erosion will affect the normal operation of the steam turbine, so the steam turbine blades need to be maintained or replaced regularly.

[0004] For the installation of turbine blades, a T-shaped limit block is cast at the root of the blade, a circle of limit grooves is opened on the side of the disc, and an installation groove is opened at a certain position on the side of the disc, and then multiple groups of blades are sequentially engaged into the limit grooves from the installation grooves. Each group of blades enters from the installation groove and then rotates along the circumferential direction of the disc so that each group of blades is stacked together. This method of blade installation is more troublesome for later replacement and maintenance. During installation, most blades need to be installed by rotating around the disc. When a group of blades needs to be replaced and repaired, the blades distributed on both sides need to be removed first. Summary of the invention

[0005] Based on this, the object of the present invention is to provide a last-stage blade of a thermal power steam turbine and a thermal power steam turbine using the blade, so as to solve the technical problems mentioned in the above background.

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical solution: a thermal power steam turbine last-stage blade and a thermal power steam turbine using the blade, comprising a steam turbine, a wheel disc is arranged inside the steam turbine, and blades are movably mounted on the side of the wheel disc, a locking groove for locking the blades is opened on the side of the wheel disc, and a mounting groove for mounting the blades is opened on the side of the wheel disc, and a cover plate is arranged on the side of the wheel disc to press the blades.

[0007] By adopting the above technical solution, by opening a snap-fit ​​groove and an installation groove on the side of the wheel disc, the blades can enter the snap-fit ​​groove of the wheel disc through the installation groove of the wheel disc. The snap-fit ​​groove of the wheel disc can limit the blades in the radial direction to prevent the blades from flying out during rotation. Then the blades in the snap-fit ​​groove of the wheel disc are pressed tightly by using a cover plate. The cover plate matches the wheel disc and the blades to narrow the installation gap and reduce the water vapor entering the installation groove and the snap-fit ​​groove of the wheel disc. The cover plate is not only used to fill the gap between the wheel disc and the blades, but also can squeeze the blades so that the blades are firmly installed in the wheel disc.

[0008] The present invention is further configured such that the blades are movably mounted in multiple groups on the side of the wheel disc, and the multiple groups of blades are evenly distributed.

[0009] Preferably, a plurality of groups of evenly distributed blades are movably mounted on the side of a wheel disc, and the wheel disc drives the blades to rotate, thereby forming a working steam turbine rotor.

[0010] The present invention is further configured such that the blade includes a blade body, and a blade root is provided at the bottom of the blade body, and a limiting groove is opened at the bottom of the blade root, and a T-block is provided at the bottom of the blade root, and the T-block matches the engaging groove, and the T-block matches the mounting groove.

[0011] Preferably, a T-block is provided at the bottom of the blade for engaging with the wheel disc, and the T-block matches the engaging groove, so that the blade can be limited in the radial direction of the wheel disc, and the blade will not be affected by the centrifugal force when the wheel disc rotates at high speed.

[0012] The present invention is further configured such that the side of the wheel disc is provided with an outer convex ring for limiting the blades, and two groups of the outer convex rings are provided, and the outer convex rings and the limiting grooves match each other.

[0013] Preferably, an outer convex ring is provided on the side of the wheel disc, and the outer convex ring matches the limiting groove of the blade, so that when the blade is engaged in the wheel disc, the blade and the wheel disc are more stable.

[0014] The present invention is further configured such that the cover plate and the wheel disc are movably mounted by bolts, and four groups of cover plates are provided.

[0015] Preferably, a cover plate is provided for pressing multiple groups of blades, so that the installation and removal of the blades are more convenient. By loosening the bolts that fasten the cover plate, the blades pressed by the group of cover plates can be replaced and repaired. Four groups of cover plates are provided, and the four groups of cover plates can be spliced ​​into a circular ring, which can press a circle of blades installed on the side of the wheel.

[0016] The present invention is further configured such that a pressing block matching the wheel disc and the blades is disposed on the side of the cover plate.

[0017] Preferably, by providing a cover plate, the cover plate can fill the gap after the blades are installed on the wheel disc, and the cover plate can squeeze the blades to make the blades more stable in the wheel disc.

[0018] In summary, the present invention mainly has the following beneficial effects:

[0019] The present invention provides multiple groups of engaging grooves on the wheel disc, and the side surfaces of each group of engaging grooves are provided with installation grooves, so that each group of blades can be independently installed and removed when installed in the engaging grooves, and then a circle of blades installed around the wheel disc is compressed by a circular cover plate, and the circular cover plate is divided into four groups, and then the multiple groups of blades are also divided into four groups for removal and installation, so that the installation of the blades is relatively simple and easy, and the later replacement of the blades is also more convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the appearance of the steam turbine of the present invention;

[0021] Figure 2 It is a schematic diagram of the installation of the wheel disc, blades and cover plate of the present invention;

[0022] Figure 3 It is a schematic diagram of the cover plate structure of the present invention;

[0023] Figure 4 It is a schematic diagram of the installation of the wheel disc and blades of the present invention;

[0024] Figure 5 It is a schematic diagram of the structure of the roulette wheel of the present invention;

[0025] Figure 6 For the present invention Figure 4 A in the enlarged view;

[0026] Figure 7 For the present invention Figure 5 The enlarged view of point B in the figure;

[0027] Figure 8 It is a schematic diagram of the blade structure of the present invention.

[0028] Description of reference numerals:

[0029] 1. Steam turbine; 2. Wheel disc; 3. Engagement groove; 4. Mounting groove; 5. External convex ring; 6. Blade; 601. Blade body; 602. Blade root; 603. T-block; 604. Limiting groove; 7. Cover plate. DETAILED DESCRIPTION

[0030] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0031] The following describes an embodiment of the present invention based on its overall structure.

[0032] See also Figure 1-8 A thermal power steam turbine final stage blade and a thermal power steam turbine using the blade, comprising a steam turbine 1, a wheel disc 2 is arranged inside the steam turbine 1, and a blade 6 is movably mounted on the side of the wheel disc 2, the wheel disc 2 and a plurality of groups of blades 6 are assembled to form a rotor of the steam turbine 1, a clamping groove 3 for clamping the blade 6 is opened on the side of the wheel disc 2, and a mounting groove 4 for mounting the blade 6 is opened on the side of the wheel disc 2, a cover plate 7 capable of pressing the blade 6 is arranged on the side of the wheel disc 2, and the clamping groove 3 and the mounting groove 4 are opened on the side of the wheel disc 2, thereby The blades 6 can enter the engaging grooves 3 of the wheel disc 2 through the mounting grooves 4 of the wheel disc 2. The engaging grooves 3 of the wheel disc 2 can limit the blades 6 in the radial direction to prevent the blades 6 from flying out during rotation. Then the cover plate 7 is used to press the blades 6 in the engaging grooves 3 of the wheel disc 2. The cover plate 7 matches the wheel disc 2 and the blades 6 to narrow the installation gap and reduce the water vapor entering the mounting grooves 4 and the engaging grooves 3 of the wheel disc 2. The cover plate 7 is not only used to fill the gap between the wheel disc 2 and the blades 6, but also can squeeze the blades 6 so that the blades 6 are firmly installed in the wheel disc 2.

[0033] In the above embodiments, please refer to Figure 2 Multiple groups of blades 6 are movably installed on the side of the wheel disc 2, and the multiple groups of blades 6 are evenly distributed. By movably installing multiple groups of evenly distributed blades 6 on the side of the wheel disc 2, the wheel disc 2 drives the blades 6 to rotate, forming a working turbine 1 rotor.

[0034] In the above embodiments, please refer to Figure 6 and Figure 8 The blade 6 includes a blade body 601, and a blade root 602 is arranged at the bottom of the blade body 601, and a limiting groove 604 is opened at the bottom of the blade root 602, and a T-block 603 is arranged at the bottom of the blade root 602, and the T-block 603 matches the engaging groove 3, and the T-block 603 matches the mounting groove 4. By arranging the T-block 603 at the bottom of the blade 6 for engaging with the wheel disc 2, the T-block 603 matches the engaging groove 3, and then the blade 6 can be limited in the radial direction of the wheel disc 2, and when the wheel disc 2 rotates at high speed, the blade 6 will not be affected by the centrifugal force.

[0035] In the above embodiments, please refer to Figure 7 and Figure 8An outer convex ring 5 for limiting the blade 6 is provided on the side of the wheel disc 2, and two groups of the outer convex rings 5 ​​are provided, and the outer convex rings 5 ​​match the limiting grooves 604. By providing the outer convex ring 5 on the side of the wheel disc 2, and matching the outer convex ring 5 with the limiting grooves 604 of the blade 6, when the blade 6 is engaged in the wheel disc 2, the blade 6 and the wheel disc 2 are more stable.

[0036] In the above embodiments, please refer to Figure 2 The cover plate 7 and the wheel disc 2 are movably installed by setting bolts, and four groups of cover plates 7 are provided. By setting the cover plates 7 to compress multiple groups of blades 6, the installation and removal of the blades 6 are more convenient. By loosening the bolts for fastening the cover plates 7, the blades 6 compressed by the group of cover plates 7 can be replaced and repaired. There are four groups of cover plates 7, and the four groups of cover plates 7 can be spliced ​​into a ring, which can compress a circle of blades 6 installed on the side of the wheel disc 2.

[0037] In the above embodiments, please refer to Figure 3 A pressing block matching the wheel disc 2 and the blade 6 is arranged on the side of the cover plate 7. By setting the cover plate 7, the cover plate 7 can fill the gap after the blade 6 is installed on the wheel disc 2, and the cover plate 7 can squeeze the blade 6 to make the blade 6 more stable in the wheel disc 2.

[0038] The present invention is in specific operation: in the later stage of work, when the staff needs to inspect and maintain the last-stage blades 6 of the steam turbine 1, the steam turbine 1 is disassembled first, and then the severity of the water erosion of the blades 6 installed on the side of the wheel disc 2 is observed. When the blades 6 need to be replaced, the staff now loosens and removes the bolts of the four sets of cover plates 7, and then knocks and removes the four sets of cover plates 7 with tools, because the cover plates 7 and the blades 6 and the wheel disc 2 are tightly engaged, and then the staff replaces the blades 6 with more serious water erosion. When replacing the blades 6, the T-block 603 at the bottom of the blade 6 is used to engage into the installation groove 4 along the axial direction of the wheel disc 2, and then the blade 6 is rotated along the circumferential direction of the wheel disc 2, and the blade 6 is engaged into the engaging groove 3. The limiting groove 604 of the blade 6 will engage with the outer convex ring 5. When all the blades 6 that need to be replaced are replaced, the multiple sets of cover plates 7 are pressed onto the wheel disc 2 again, and then the cover plates 7 and the wheel disc 2 are further pressed with bolts.

[0039] Although an embodiment of the present invention has been shown and described, this specific embodiment is merely an explanation of the present invention and is not a limitation of the invention. The specific features, structures, materials or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. After reading this specification, those skilled in the art may make modifications, substitutions and variations to the embodiments without creative contributions as needed without departing from the principles and purpose of the present invention. However, as long as they are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A thermal power steam turbine last stage blade and a thermal power steam turbine using the blade, comprising a steam turbine (1), characterized in that: A wheel disc (2) is arranged inside the steam turbine (1), and blades (6) are movably mounted on the side of the wheel disc (2), a locking groove (3) for locking the blades (6) is provided on the side of the wheel disc (2), and a mounting groove (4) for mounting the blades (6) is provided on the side of the wheel disc (2), and a cover plate (7) capable of pressing the blades (6) is provided on the side of the wheel disc (2).

2. A thermal power steam turbine final stage blade and a thermal power steam turbine using the blade according to claim 1, characterized in that: The blades (6) are movably mounted in multiple groups on the side of the wheel disc (2), and the multiple groups of blades (6) are evenly distributed.

3. A thermal power steam turbine last stage blade and a thermal power steam turbine using the blade according to claim 2, characterized in that: The blade (6) comprises a blade body (601), and a blade root (602) is arranged at the bottom of the blade body (601), and a limiting groove (604) is provided at the bottom of the blade root (602), and a T-shaped block (603) is arranged at the bottom of the blade root (602), and the T-shaped block (603) matches the engaging groove (3), and the T-shaped block (603) matches the mounting groove (4).

4. A thermal power steam turbine last stage blade and a thermal power steam turbine using the blade according to claim 3, characterized in that: An outer convex ring (5) for limiting the position of the blades (6) is arranged on the side of the wheel disc (2), and two groups of the outer convex rings (5) are arranged, and the outer convex rings (5) and the limiting grooves (604) match each other.

5. A thermal power steam turbine last stage blade and a thermal power steam turbine using the blade according to claim 4, characterized in that: The cover plate (7) and the wheel disc (2) are movably mounted by means of bolts, and four groups of cover plates (7) are provided.

6. A thermal power steam turbine last stage blade and a thermal power steam turbine using the blade according to claim 5, characterized in that: A pressing block matching the wheel disc (2) and the blades (6) is arranged on the side of the cover plate (7).

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