Turbine shaft end centrifugal labyrinth combined gas seal

Abstract

The utility model discloses turbine shaft end centrifugal labyrinth combined steam seal relates to turbine technical field, including centrifugal disc, the centrifugal disc is fixed on the rotor shaft sealing section through the mode of welding or inlay, a plurality of high and low sealing teeth are arranged on the rotor shaft interval equidistance, preferably, the centrifugal disc is arranged at the front side of sealing tooth, preferably, the outer surface of centrifugal disc is annularly arranged with spiral groove, the centrifugal disc adopts novel high -strength material to make, the supercritical steam turbine novel shaft end non -contact centrifugal labyrinth combined steam seal of the utility model can avoid the dynamic and static rub of turbine operation, reduce turbine shaft end air leakage, shorten the steam turbine axial dimension, save resources, improve the economy of unit operation, improve the safety of unit operation simultaneously, and its simple structure is practical, and the sealing effect is good, reduces the leakage, and is easy to promote.

Description

Technical Field

[0001] This utility model relates to the field of steam turbine technology, specifically to a centrifugal labyrinth combined steam seal at the shaft end of a steam turbine. Background Technology

[0002] The power industry is a crucial foundation of the national economy and a key and pioneering sector in the national economic development strategy. In recent years, rapid domestic economic development has driven the rapid growth of the power industry, with my country's installed power generation capacity continuously increasing. Currently, China's total installed thermal power capacity is approximately 1.36 billion kilowatts. However, with the structural adjustment of my country's power industry, future thermal power plants will inevitably move towards greater efficiency and environmental friendliness. Energy conservation, environmental improvement, increased power generation efficiency, and reduced power generation costs have become inevitable trends. Therefore, finding efficient, energy-saving, and low-carbon technologies and equipment is an urgent and crucial task for thermal power plants.

[0003] In thermal power plants, the flow path of steam turbines has undergone numerous improvements driven by computational fluid dynamics, resulting in enhanced performance. However, with the increase in steam parameters, steam leakage has become the primary factor restricting efficiency improvement. To reduce leakage and improve unit efficiency, turbine manufacturers commonly install various steam seals, such as diaphragm seals, blade tip seals, and cylinder end seals (also known as shaft seals). According to statistics, steam leakage accounts for 29% of the total stage losses in a steam turbine. Energy losses caused by shaft end seal leakage can reduce turbine efficiency by 3%–4%, representing one-third of the internal turbine losses. Shaft end seal leakage also leads to lubricant deterioration and component corrosion, seriously threatening unit safety. To reduce steam leakage and improve unit operating safety and economy, researchers both domestically and internationally have conducted extensive research on the modification and design of shaft end seals.

[0004] Traditional labyrinth steam seals use multi-stage annular toothed plates to form a tortuous flow channel with the shaft, gradually throttling and depressurizing the steam to reduce leakage. They have a simple structure and good sealing effect, but require a relatively long shaft seal section. Brush steam seals use dense metal wires (cobalt-based or nickel-based alloys) in slight contact with the shaft to form a dynamic seal. Their leakage is less than that of labyrinth seals, but the brushes wear significantly after long-term operation, requiring periodic replacement. The Wang Changchun type steam seal is an improved honeycomb seal. Based on the traditional honeycomb seal, it adds a helical tooth (or stepped tooth) design, forming a "honeycomb + labyrinth" composite seal, further reducing leakage. However, due to high machining precision requirements and the complex helical tooth structure, the entire component must be replaced after wear, making local maintenance impossible. This results in high production and maintenance costs, making it difficult for small and medium-sized units or low-parameter steam turbines to afford the modification costs.

[0005] Therefore, a centrifugal labyrinth steam seal combination for turbine shaft ends is proposed. Utility Model Content

[0006] The purpose of this invention is to provide a centrifugal labyrinth combined steam seal for turbine shaft ends, in order to solve the problems of rubbing and excessive steam leakage loss in the operation of turbine shaft sealing systems mentioned in the background art. It proposes a new type of shaft end steam seal that is non-contact and reduces steam leakage loss, thereby reducing the leakage of the turbine unit, improving the unit's economy, and saving a lot of resources.

[0007] To achieve the above objectives, this utility model provides the following technical solution: a centrifugal labyrinth combined steam seal for a steam turbine shaft end, comprising a centrifugal disc, wherein the centrifugal disc is mounted and fixed on the rotor shaft sealing section by welding or fitting, and a plurality of high and low sealing teeth are arranged at equal intervals on the rotor shaft.

[0008] Preferably, the centrifugal disk is arranged in front of the sealing teeth.

[0009] Preferably, the outer surface of the centrifugal disk is provided with spiral grooves arranged in a ring.

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

[0011] This invention relates to a novel non-contact centrifugal labyrinth steam seal for supercritical steam turbine shaft ends. This seal can prevent dynamic and static friction during turbine operation, reduce steam leakage at the turbine shaft ends, shorten the axial dimension of the turbine, save resources, improve the economic efficiency of unit operation, and enhance the safety of unit operation. Its structure is simple, practical, and easy to promote. Attached Figure Description

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

[0013] Figure 2 This is a schematic diagram of the turbine main shaft structure of this utility model;

[0014] Figure 3 This is a schematic diagram of the centrifugal disc structure of this utility model;

[0015] Figure 4 This is a schematic diagram of the centrifugal disc structure of this utility model;

[0016] In the diagram: 1. Centrifugal disc; 2. Sealing teeth; 3. Rotor shaft; 4. Spiral groove. Detailed Implementation

[0017] The technical solutions of the present 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 the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0018] Example: Please refer to Figure 1-4 This utility model provides a technical solution: a centrifugal labyrinth steam seal at the end of a steam turbine shaft, including a centrifugal disc 1. The centrifugal disc 1 is fixed to the sealing section of the rotor shaft 3 by welding or fitting. Several high and low sealing teeth 2 are arranged at equal intervals on the rotor shaft 3. The centrifugal disc 1 is arranged in front of the sealing teeth 2. The high-speed rotation of the steam turbine rotor shaft 3 forces the centrifugal disc 1 to rotate at high speed. The centrifugal force generated by the rotation of the centrifugal disc 1 throws the steam in the cylinder radially out along the slot, reducing the amount of steam entering the leakage gap of the sealing teeth 2. After the medium enters the sealing tooth 2 section, the steam is throttled and depressurized step by step, and its disorder is enhanced, thereby reducing steam leakage and achieving the sealing effect.

[0019] Furthermore, a spiral groove 4 is arranged in a ring on the outer surface of the centrifugal disc 1. By rotating the centrifugal disc 1 at high speed, the medium can be thrown out radially along the spiral groove 4, reducing the medium entering the leakage gap of the sealing teeth 2, thereby achieving the sealing purpose.

[0020] The working principle is as follows: The novel non-contact centrifugal labyrinth steam seal for supercritical steam turbines consists of a centrifugal disc 1 made of a new high-strength material and several sealing teeth 2. The centrifugal disc 1 is fixed to the sealing end of the turbine rotor shaft 3 by welding or fitting. High and low sealing teeth 2 are evenly arranged behind it, and spiral grooves 4 are arranged in a ring on the centrifugal disc 1. During operation, the high-speed rotation of the rotor shaft 3 forces the centrifugal disc 1 to rotate at high speed. The centrifugal force generated by the rotation of the centrifugal disc 1 throws the steam in the cylinder radially out along the grooves, reducing the amount of steam entering the leakage gap of the sealing teeth 2. After the medium enters the sealing tooth 2 section, the steam is progressively throttled and depressurized, increasing its disorder and thus reducing steam leakage, thereby achieving a sealing effect.

[0021] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A centrifugal labyrinth steam seal at the shaft end of a steam turbine, characterized in that: It includes a centrifugal disc (1), which is fixed to the sealing section of the rotor shaft (3) by welding or fitting. The rotor shaft (3) has a number of high and low sealing teeth (2) arranged at equal intervals.

2. The turbine shaft end centrifugal labyrinth combined steam seal according to claim 1, characterized in that: The centrifugal disk (1) is arranged on the front side of the sealing tooth (2).

3. The turbine shaft end centrifugal labyrinth combined steam seal according to claim 1, characterized in that: The centrifugal disk (1) has spiral grooves (4) arranged in a ring on its outer surface.

Images