Novel steam turbine sealing structure

Abstract

The utility model discloses a novel steam turbine sealing structure, which belongs to the technical field of steam turbine shaft sealing, and comprises a steam seal body arranged around a rotor step, a rectifying ring arranged around the outlet side of the steam seal body, a notch for generating an expansion chamber processed at the lower part of the rectifying ring, and steam seal teeth arranged at the bottom of the steam seal body, a gap is formed between the steam sealing teeth and the rotor step, one part of airflow flows through the airflow dissipation cavity, and the other part of airflow passes through the gap and the expansion cavity. Therefore, according to the novel steam turbine sealing structure, the rectifying ring is additionally arranged in the incoming flow cavity, high-temperature steam leakage is reduced, unit efficiency is improved, and energy consumption is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of steam turbine sealing, in particular to a novel steam turbine sealing structure. Background Art

[0002] At present, most steam turbine units in domestic power plants adopt more labyrinth gland seals, which have the characteristics of simple structure, convenient processing and manufacturing, and low production cost. However, this type of gland seal is not airtight but has gaps. Because the labyrinth gland seal has disadvantages such as easy wear and large steam leakage, it seriously reduces the thermal efficiency and has an impact.

[0003] The forms of sealing usually include static sealing and dynamic sealing. Static sealing: Usually used between fixed components, such as the sealing between the housing and the end cover. Static sealing requires materials with high temperature resistance and corrosion resistance to ensure long-term stable sealing performance. Dynamic sealing: Mainly used between rotating components, such as the sealing between the rotor step and the housing. These seals usually use designs such as rotating sealing rings, piston rings or gas seals to reduce frictional losses and leakage.

[0004] This application adopts dynamic sealing and designs a novel sealing structure by referring to the principle of Tesla valve. By adding a rectifying ring in the cavity of the incoming flow, a jet flow opposite to the flow direction is formed to block the reverse flow of high-temperature steam in the cavity, thereby reducing the leakage of high-temperature steam. Summary of the Utility Model

[0005] To solve the above problems, the utility model provides a novel steam turbine sealing structure. By adding a rectifying ring in the cavity of the incoming flow, a jet flow opposite to the flow direction is formed to block the reverse flow of high-temperature steam in the cavity, thereby reducing the leakage of high-temperature steam.

[0006] To achieve the above object, the utility model provides a novel steam turbine sealing structure, which includes a gland body arranged around the rotor step, a rectifying ring is arranged around the gland body near the outlet side, a notch for generating an expansion chamber is processed at the lower part of the rectifying ring, gland teeth are arranged at the bottom of the gland body, gaps are formed between the gland teeth and the rotor step, a part of the air flow flows through the air flow dissipation cavity, and another part of the air flow passes through the gaps and the expansion chamber.

[0007] Preferably, four rectifying ring fixing parts are arranged on the rectifying ring, and the rectifying ring fixing parts are fixed on the gland body by bolts. A cavity is formed between the rectifying ring and the gland body, and a part of the air flow enters the gap between the gland teeth and the rotor step through the cavity.

[0008] Preferably, the notch is arranged opposite to the step on the rotor step, and the width of the step is greater than the total width of the notch and the jet flow.

[0009] Preferably, a cavity for placing the rectifying ring is provided at a position on the gland body corresponding to the rectifying ring, and the size of the cavity is larger than that of the rectifying ring.

[0010] Preferably, the inclination angle of the rectifying ring is opposite to the air flow direction to prevent high-temperature steam from overflowing.

[0011] Preferably, the left and right sides of the gland body are welded by argon arc welding. A rotor step is provided on the circumferential side of the rotating shaft, and the gland body is arranged on the shaft gland sleeve.

[0012] Preferably, the outer side of the rectifying ring is arc-shaped.

[0013] Preferably, the gland teeth include long steam-blocking teeth and short steam-blocking teeth.

[0014] Therefore, the present utility model provides a new steam turbine sealing structure. By adding a rectifying ring in the cavity of the incoming flow, the leakage of high-temperature steam is reduced, the efficiency of the unit is improved, and the energy consumption is reduced.

[0015] The technical solution of the present utility model will be further described in detail below with reference to the drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings herein are incorporated into the specification and form a part of the specification, showing embodiments consistent with the present application, and are used together with the specification to explain the principles of the present application.

[0017] Figure 1 is the original model of the steam turbine sealing structure;

[0018] Figure 2 is the internal structure schematic diagram of the present application;

[0019] Figure 3 is the enlarged view of part A of the present application;

[0020] Figure 4 is the structural diagram of the rectifying ring without the rectifying ring fixing part;

[0021] Figure 5 is the structural diagram of another angle of the present application.

[0022] REFERENCE NUMERALS

[0023] 1, rotating shaft; 2, gland body; 3, air flow dissipation cavity; 4, long steam-blocking teeth; 5, short steam-blocking teeth; 6, rotor step; 7, rectifying ring; 8, external environment; 9, inner cylinder; 10, air outlet; 11, air inlet; 12, fixing bolt; 13, rectifying ring cavity; 14, notch; 15, expansion chamber; 16, rectifying ring fixing part; 17, bolt. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] The technical solution of the present utility model will be further described below with reference to the accompanying drawings and embodiments.

[0025] a. Original model analysis

[0026] The original model of the steam turbine sealing structure is as shown in Figure 1 From the basic principle, the steam turbine sealing structure consists of the following parts: outlet 10, gland body 2, inlet 11, rotor step 6, and fixing bolts 12. The function of the gland body 2 is to prevent steam from diffusing to the outside, and the function of the fixing bolts 12 is to fix the rotor step 6. Assuming that the gland body 2 and the rotor step 6 remain stationary, steam enters the inside of the sealing structure from the right inlet 11. The air flow passes through the narrow gap above the rotor step 6 and flows forward under the action of the high-pressure difference between the inlet and outlet, accompanied by the generation of large and small eddies. The existence of the eddy phenomenon is beneficial to energy dissipation and pressure loss because in the area where the eddies exist, the intensity of the air flow collision and extrusion inside the sealing structure is higher, and the resulting pressure loss is also more, resulting in a reduction in the leakage amount. Finally, it flows out from the left outlet 10 to complete the blockage of the air flow inside the steam turbine sealing structure. Due to the long-term operation of the unit, the shaft seal is worn, especially when the unit participates in peak shaving and variable working conditions frequently, with many start-stop times and cold start times, the shaft seal wear is more serious, the gap becomes larger, so the steam leakage increases, and the sealing effect is poor, and the economy of the unit is poor.

[0027] Embodiment 1

[0028] As shown in Figures 2 - 5 The present utility model provides a new type of steam turbine sealing structure, including a gland body 2 arranged around the rotor step 6. A rectifying ring 7 is arranged around the outlet side of the gland body 2. A notch 14 for generating an expansion chamber 15 is processed at the lower part of the rectifying ring 7. Sealing teeth are arranged at the bottom of the gland body 2, and a gap is generated between the sealing teeth and the rotor step 6. Due to the pressure difference between the inner cylinder 9 and the external environment 8, high-temperature steam leaks to the external environment 8. The gas enters the inside of the gland body 2 from the inner cylinder 9. Part of the air flow flows through the air flow dissipation cavity 3, and the other part of the air flow passes through the gap and the expansion chamber 15.

[0029] The left and right sides of the gland body 2 are welded into one body by argon arc welding. A rotor step 6 is arranged on the circumferential side of the rotating shaft 1, and the gland body 2 is arranged on the shaft seal sleeve. Long steam-blocking teeth 4 and short steam-blocking teeth 5 are arranged at intervals on the gland body 2 facing the rotating shaft 1.

[0030] At the position on the gland body 2 corresponding to the straightening ring 7, there is a straightening ring cavity 13 for placing the straightening ring 7. The size of the straightening ring cavity 13 is larger than that of the straightening ring 7 to facilitate more fluid to flow through. There are four straightening ring fixing parts 16 on the straightening ring 7, and the straightening ring fixing parts 16 are fixed on the gland body 2 through bolts 17. The part of the straightening ring 7 without the straightening ring fixing parts 16 forms a cavity with the gland body 2, and part of the air flow enters the gap between the gland teeth and the rotor step 6 through the cavity. The introduction of the straightening ring 7 spontaneously forms a jet flow opposite to the flow direction, increasing the range of the eddy currents on both sides of the rotor step 6, which can block the reverse flow of high-temperature steam, thereby reducing leakage.

[0031] The outer side of the straightening ring 7 is arc-shaped, reducing the pressure loss of the jet flow channel and increasing the intensity of the jet flow. The position of the straightening ring 7 is close to the outlet 10 side of the gland body 2, increasing the mass flow rate of the jet flow channel.

[0032] The notch 14 is set opposite to the step on the rotor step 6, and the width of the step is greater than the total width of the notch 14 and the jet flow. The setting of the notch 14 adds an expansion chamber 15, which is beneficial to the generation of eddy currents and dissipates the energy of the leakage flow. The width of the step is wider than the total width of the notch 14 at the lower part of the straightening ring 7 and the jet flow, ensuring sufficient throttling effect and jet flow blocking effect; the inclination angle of the straightening ring 7 is opposite to the air flow direction, against the direction of the leakage flow, and forms a jet flow channel with the straightening ring 7.

[0033] Therefore, the present application provides a novel steam turbine sealing structure. By adding a straightening ring in the cavity of the incoming flow, the leakage of high-temperature steam is reduced, the efficiency of the unit is improved, and the energy consumption is reduced.

[0034] In the description of this specification, the descriptions referring to terms such as "an experimental example", "example", "specific example", etc. mean that the specific features, structures, materials or characteristics described in connection with the experimental example or example are included in at least one experimental example or example of the present utility model. In this specification, the schematic expressions of the above terms do not necessarily refer to the same experimental example or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more experimental examples or examples.

[0035] Finally, it should be noted that the above experimental examples are only used to illustrate the technical solutions of the present utility model and are not intended to limit them. Although the present utility model has been described in detail with reference to the preferred experimental examples, those of ordinary skill in the art should understand that they can still modify the technical solutions of the present utility model or make equivalent replacements, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present utility model.

Claims

1. A new type of steam turbine sealing structure, characterized in that, It includes a gland body arranged around the rotor step, a fairing ring is arranged around the outlet side of the gland body, a notch for generating an expansion chamber is machined at the lower part of the fairing ring, gland teeth are arranged at the bottom of the gland body, gaps are generated between the gland teeth and the rotor step, a part of the air flow passes through the air flow dissipation cavity, and another part of the air flow passes through the gaps and the expansion chamber; Four fairing ring fixing parts are arranged on the fairing ring, the fairing ring fixing parts are fixed on the gland body by bolts, a cavity is formed between the fairing ring and the gland body, and part of the air flow enters the gap between the gland teeth and the rotor step through the cavity; The notch is arranged opposite to the step on the rotor step, and the width of the step is greater than the total width of the notch and the jet; A cavity for placing the fairing ring is arranged at the position corresponding to the fairing ring on the gland body, and the size of the cavity is larger than the size of the fairing ring; The inclination angle of the fairing ring is opposite to the air flow direction, which hinders the overflow of high-temperature steam; The outer side of the fairing ring is arc-shaped.

2. A novel steam turbine sealing structure according to claim 1, characterized in that, The left and right sides of the gland body are welded by argon arc welding, a rotor step is arranged on the circumferential side of the rotating shaft, and the gland body is arranged on the shaft seal sleeve.

3. A novel steam turbine sealing structure according to claim 1, characterized in that, The gland teeth include long steam-blocking teeth and short steam-blocking teeth.

Images