A last stage blade of a steam turbine

Abstract

This utility model discloses a turbine last-stage blade, including a blade and a blade root. One end of the blade is connected to the upper surface of the blade root. The blade is an arc-shaped plate. A first thickened protrusion is reserved at the connection between the blade and the blade root on the inner arc surface of the blade. The outer surface of the first thickened protrusion is inclined. A second thickened protrusion is provided between the blade and the outer arc surface. A positioning hole is opened on the blade at the second thickened protrusion. A limit block is provided at the end of the blade away from the blade root. This utility model has a reasonable structure. The first thickened protrusion greatly improves the structural strength between the blade and the blade root, thereby ensuring the stability of the last-stage blade. The outer surface of the first thickened protrusion is inclined, thereby reducing wind resistance. The second thickened protrusion ensures the structural strength of the blade at the positioning hole and avoids deformation and bending.

Description

Technical Field

[0001] This utility model relates to the field of steam turbine blade technology, specifically a steam turbine last-stage blade. Background Technology

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

[0003] Steam turbines typically have multiple sets of moving blades and stationary blades. The longer moving blades are usually the last-stage blades. In existing steam turbines, the last-stage blades are directly connected to the blade root without any reinforcement structure, which makes them prone to breakage at the blade root. When installing the last-stage blades, all blades are usually bolted to a ring to ensure the stability of all last-stage blades. However, the connection between the blade and the ring is also one of the areas prone to deformation. Therefore, there is an urgent need for an improved technology to solve this problem in the existing technology. Utility Model Content

[0004] The purpose of this utility model is to provide a turbine last-stage blade, which greatly improves the structural strength between the blade and the blade root through a first thickened protrusion, thereby ensuring the stability of the last-stage blade, and ensures the structural strength of the blade at the positioning hole through a second thickened protrusion, avoiding deformation and bending, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a turbine last-stage blade, comprising a blade and a blade root, one end of the blade being connected to the upper surface of the blade root, the blade being an arc-shaped plate, a first thickened protrusion pre-reserved at the connection between the blade and the blade root on the inner arc surface of the blade, the outer surface of the first thickened protrusion being a slope, a second thickened protrusion being provided between the blade and the outer arc surface, a positioning hole being provided on the blade at the location of the second thickened protrusion, and a limit block being provided at the end of the blade away from the blade root.

[0006] Preferably, the present invention provides a turbine last-stage blade, wherein the blade root has a plurality of slots at the end away from the blade.

[0007] Preferably, the turbine last-stage blade provided by this utility model is an integral structure comprising the first thickened protrusion, the second thickened protrusion, the blade, the blade root, and the limiting block.

[0008] Preferably, the present invention provides a turbine last-stage blade, wherein the blade gradually twists from the end near the blade root to the end away from the blade root.

[0009] Preferably, the present invention provides a turbine last-stage blade, wherein one end of the limiting block is provided with a protrusion, and the other end of the limiting block is provided with a limiting groove that matches the protrusion.

[0010] Compared with the prior art, the beneficial effects of this utility model are:

[0011] A first thickened protrusion is reserved at the connection between the blade and the blade root, and a second thickened protrusion is provided on the surface of the blade. The first thickened protrusion greatly improves the structural strength between the blade and the blade root, thereby ensuring the stability of the last stage blade. The outer surface of the first thickened protrusion is inclined, thereby reducing wind resistance. The second thickened protrusion ensures the structural strength of the blade at the positioning hole and avoids deformation and bending. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the structure of this utility model;

[0013] Figure 2 For the appendix Figure 1 Schematic diagram of the angle transformation structure;

[0014] Figure 3 This is a side view cross-sectional structural diagram of the present invention;

[0015] Figure 4 This is a schematic diagram of the limit block.

[0016] In the diagram: 1. Leaf blade; 2. Leaf root; 3. First thickened protrusion; 4. Second thickened protrusion; 5. Positioning hole; 6. Limiting block; 7. Slot; 8. Protrusion; 9. Limiting groove. Detailed Implementation

[0017] The technical solution of this utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0018] It should be noted that in the description of this utility model, the terms "inner", "outer", "upper", "lower", "both sides", "one end", "the other end", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0019] Please see Figure 1-3 This utility model provides a technical solution: a last-stage turbine blade, including a blade 1 and a blade root 2. One end of the blade 1 is connected to the upper surface of the blade root 2. The blade root 2 has several slots 7 at the end away from the blade 1. The slots 7 are used to connect the blade root 2 with the turbine inner ring mounting seat, thereby ensuring the stability of the last-stage blade and preventing the blade 1 from loosening. The blade 1 is an arc-shaped plate, and the blade 1 gradually twists from the end near the blade root 2 to the end away from the blade root 2 to ensure that steam can be smoothly transmitted backward when the blade 1 rotates. A first thickened protrusion 3 is reserved at the connection between the blade 1 and the blade root 2 and on the inner arc surface of the blade 1. The outer surface of the first thickened protrusion 3 is a slope. The outer arc surface is provided with a second thickened protrusion 4. The blade 1 is provided with a positioning hole 5 at the second thickened protrusion 4. A limiting block 6 is provided at the end of the blade 1 away from the blade root 2. A protrusion 8 is provided at one end of the limiting block 6, and a limiting groove 9 matching the protrusion 8 is provided at the other end of the limiting block 6. After the last stage blade is installed, the limiting blocks 6 of two adjacent last stage blades are matched end to end. The protrusion 8 of one limiting block 6 is inserted into the limiting groove 9 of the other limiting block 6 to ensure that the outer end of the blade 1 will not be misaligned. The first thickened protrusion 3, the second thickened protrusion 4, the blade 1, the blade root 2 and the limiting block 6 are integrated into one structure, which is convenient for processing and ensures the stability of the entire last stage blade.

[0020] Installation method and operating principle: First, a blank of the last-stage blade is prepared. Then, several slots 7 are made in the blade root 2 by milling. The blade 1 is then prepared by milling, and a limiting block 6 is reserved at the top of the blade 1. At the same time, a first thickened protrusion 3 is reserved at the connection between the blade 1 and the blade root 2 and on the inner side of the blade 1, and a second thickened protrusion 4 is reserved on the outer surface of the blade 1 and at the positioning hole 5, thus obtaining the last-stage blade of this application. During installation, the blade root 2 mates with the inner ring mounting seat of the turbine and is positioned by the slots 7. All the last-stage blades are connected to the intermediate ring body through the positioning holes 5 and bolts, completing the installation of the last-stage blades in the turbine. After the last-stage blades are installed, the limiting blocks 6 of two adjacent last-stage blades are connected end to end to avoid misalignment. This utility model has a reasonable structure. A first thickened protrusion 3 is reserved at the connection between the blade 1 and the blade root 2. A second thickened protrusion 4 is provided on the surface of the blade 1. The first thickened protrusion 3 greatly improves the structural strength between the blade 1 and the blade root 2, thereby ensuring the stability of the last stage blade. The outer surface of the first thickened protrusion 3 is inclined, thereby reducing wind resistance. The second thickened protrusion 4 ensures the structural strength of the blade 1 at the positioning hole 5 and avoids deformation and bending.

[0021] Any aspects of this utility model not described in detail are well-known technologies to those skilled in the art.

[0022] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solution of this utility model and not to limit it. Although this utility model has been described in detail with reference to the embodiments, those skilled in the art should understand that modifications and equivalent substitutions can be made to the technical solution of this utility model without departing from the spirit and scope of the technical solution of this utility model, and all such modifications and substitutions should be covered within the scope of the claims of this utility model.

Claims

1. A last stage blade for a steam turbine, characterized by: Includes a blade (1) and a leaf root (2). One end of the blade (1) is connected to the upper surface of the leaf root (2). The blade (1) is an arc-shaped plate. A first thickened protrusion (3) is reserved at the connection between the blade (1) and the leaf root (2) and on the inner arc surface of the blade (1). The outer surface of the first thickened protrusion (3) is a slope. A second thickened protrusion (4) is provided on the blade (1) and the outer arc surface. A positioning hole (5) is opened on the blade (1) at the second thickened protrusion (4). A limit block (6) is provided at the end of the blade (1) away from the leaf root (2).

2. A last stage blade for a steam turbine as defined in claim 1, characterized in that: The leaf root (2) has several slots (7) at the end away from the leaf blade (1).

3. The turbine last-stage blade according to claim 1, characterized in that: The first thickened protrusion (3), the second thickened protrusion (4), the blade (1), the blade root (2) and the limiting block (6) are an integral structure.

4. The turbine last-stage blade according to claim 1, characterized in that: The blade (1) gradually twists from the end near the leaf root (2) to the end away from the leaf root (2).

5. The turbine last-stage blade according to claim 1, characterized in that: One end of the limiting block is provided with a protrusion, and the other end of the limiting block is provided with a limiting groove that matches the protrusion.

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