Anti-jamming structure for medium-pressure combined valve of steam turbine

Abstract

The utility model discloses a steam turbine medium-pressure combined valve anti-jamming structure which comprises an upper lining and a lower lining, and a first stellite alloy lining and a second stellite alloy lining are arranged in the upper lining and the lower lining in a spray welding mode respectively. The surfaces of the upper bush and the lower bush are sleeved with a valve deck, the valve deck is clamped by the upper bush and the lower bush, and a sealing ring is installed on the right side face of the valve deck. A valve rod is inserted into the first stellite lining and the second stellite lining, a connecting part is arranged at the right end of the valve rod, a main steam valve disc check ring is connected to the surface of the connecting part in a sleeving mode, a main steam valve disc clamping ring is connected to the surface of the main steam valve disc check ring in a sleeving mode, and the main steam valve disc clamping ring is connected with the inner wall of the sealing ring in a sealed mode. The stellite alloy bushing is integrally formed by spray welding, so that the bonding strength of the stellite alloy is enhanced, the upper bushing and the lower bushing are prevented from being changed, valve jamming caused by falling of the stellite alloy is prevented, stable operation of the steam turbine is ensured, and the failure rate of the steam turbine is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of steam turbine valves, in particular to an anti-jamming structure for a medium-pressure combined steam valve of a steam turbine. Background Technique

[0002] The jamming of steam turbine valves is one of the common faults in thermal power plants. The reasons for the jamming defect of the medium-pressure combined steam valve of the steam turbine are as follows: The valve stem bushing of the steam valve is designed as a double-layer structure. The inner layer is a Stellite alloy thin-walled cylinder, which is interference-fitted with the outer bushing. The processing and fitting accuracy requirements are high and difficult to control. The parts outside the bushing are also interference-fitted with the bushing. In the case of two-layer interference fitting, after long-term high-temperature operation, the inner hole of the bushing may become smaller, resulting in a smaller clearance between it and the valve stem, causing jamming; The material of the original valve core part has weak high-temperature oxidation resistance. Under high-temperature working conditions, oxide scales are likely to appear on the surface of the valve core part, causing the clearance between the valve core moving parts to become smaller, resulting in poor movement of the valve core part; There are unreasonable local fitting data in the original clearance design of the parts set, resulting in valve jamming due to the following problems: The original designed clearance between the parts set is small, and the clearance becomes smaller after thermal expansion. When oxide scales appear on the parts, it is extremely easy to cause valve jamming; The interference clearance design between the valve stem bushing and the outer bushing, and between the valve stem bushing and the internally inlaid thin-walled cylinder is unreasonable, resulting in deformation of the bushing, and thus the clearance between the bushing and the valve stem is uneven in an elliptical shape, and the local clearance is small, causing valve jamming. Therefore, it is necessary to solve the problem of jamming of the medium-pressure combined steam valve of the steam turbine to ensure the normal operation of the steam turbine. Content of the Utility Model

[0003] The purpose of the utility model is to provide an anti-jamming structure for a medium-pressure combined steam valve of a steam turbine to solve the problems put forward in the above background technique.

[0004] To achieve the above purpose, the utility model provides the following technical solution: An anti-jamming structure for a medium-pressure combined steam valve of a steam turbine, including an upper bushing and a lower bushing. The inner parts of the upper bushing and the lower bushing are respectively spray-welded with a first Stellite alloy bushing and a second Stellite alloy bushing to enhance the bonding strength of the Stellite alloy and prevent the upper bushing and the lower bushing from deforming or the first Stellite alloy bushing and the second Stellite alloy bushing from falling off, causing valve jamming;

[0005] A valve cover is sleeved on the surfaces of the upper bushing and the lower bushing. The valve cover is clamped by the upper bushing and the lower bushing to ensure stable installation of the valve cover without loosening and good sealing performance. A sealing ring is installed on the right side surface of the valve cover;

[0006] The first Stellite alloy bushing and the second Stellite alloy bushing are internally inserted with a valve stem. The right end of the valve stem is provided with a connecting portion. The surface of the connecting portion is sleeved with a main steam valve disc stop ring. The surface of the main steam valve disc stop ring is sleeved with a main steam valve disc snap ring, and the main steam valve disc snap ring is hermetically connected to the inner wall of the sealing ring, improving the smoothness of the valve stem sliding.

[0007] Furthermore, a third Stellite alloy bushing is spray-welded on the inner surface of the main steam valve disc stop ring. The structure of the main steam valve disc stop ring and the third Stellite alloy bushing is more stable, and problems such as cracks and detachment will not occur.

[0008] Furthermore, a ring groove is provided on the surface of the connecting portion. A regulating valve guide pin is provided inside the ring groove. The inner wall of the main steam valve disc stop is arranged in a stepped shape, and the main steam valve disc stop ring is sleeved on the surface of the regulating valve guide pin. The regulating valve guide pin can guide the movement of the valve stem and can also prevent the valve stem from jamming.

[0009] Furthermore, a sealing sleeve is provided on the inner wall of the sealing ring. The sealing sleeve is sleeved on the surface of the main steam valve disc snap ring, and the sealing effect is good, and steam leakage problems are not likely to occur.

[0010] Compared with the prior art, the beneficial effects of the present utility model are as follows: The first Stellite alloy bushing is integrally spray-welded on the inner wall of the upper bushing, the second Stellite alloy bushing is integrally spray-welded on the inner wall of the lower bushing, and the third Stellite alloy bushing is integrally spray-welded on the inner wall of the main steam valve disc stop ring, enhancing the bonding strength of the Stellite alloy, preventing the upper bushing and the lower bushing from deforming, preventing the Stellite alloy from falling off and causing the steam valve to jam, ensuring the stable operation of the steam turbine, and reducing the failure rate of the steam turbine. Description of the Drawings

[0011] Figure 1 is a cross-sectional view of the overall assembly of the present utility model;

[0012] Figure 2 is a schematic diagram of the split of the present utility model;

[0013] Figure 3 is a schematic diagram of the structure of the upper bushing of the present utility model;

[0014] Figure 4 is a schematic diagram of the structure of the lower bushing of the present utility model.

[0015] In the figure: 1. Upper bushing; 2. Lower bushing; 3. Valve cover; 4. Valve stem; 5. Main steam valve disc snap ring; 6. Main steam valve disc stop ring; 7. Regulating valve guide pin; 8. Sealing ring; 9. Connecting portion; 10. First Stellite alloy bushing; 11. Second Stellite alloy bushing; 14. Sealing ring; 15. Sealing sleeve; 16. Third Stellite alloy bushing. Detailed Embodiment

[0016] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0017] Embodiment:

[0018] Please refer to Figures 1-4 , the present invention provides a technical solution: an anti-jamming structure for the intermediate pressure combined steam valve of a steam turbine, including an upper bushing 1 and a lower bushing 2. The upper bushing 1, the lower bushing 2, and the sealing ring 8 are made of F92 alloy steel. In a high-temperature environment, F92 alloy steel has good oxidation resistance and high-temperature creep strength. The inner parts of the upper bushing 1 and the lower bushing 2 are respectively spray-welded with a first Stellite alloy bushing 10 and a second Stellite alloy bushing 11 to increase the structural strength of the first Stellite alloy bushing 10 and the second Stellite alloy bushing 11;

[0019] A valve cover 3 is sleeved on the surfaces of the upper bushing 1 and the lower bushing 2. The valve cover 3 is clamped by the upper bushing 1 and the lower bushing. A sealing ring 8 is installed on the right side surface of the valve cover 3, and the sealing ring 8 seals the main steam valve disc snap ring 5;

[0020] A valve stem 4 is inserted into the first Stellite alloy bushing 10 and the second Stellite alloy bushing 11. The right end of the valve stem 4 is provided with a connecting portion 9. A main steam valve disc stop ring 6 is sleeved on the surface of the connecting portion 9. A main steam valve disc snap ring 5 is sleeved on the surface of the main steam valve disc stop ring 6, and the main steam valve disc snap ring 5 is hermetically connected to the inner wall of the sealing ring 8;

[0021] The main steam valve disc stop ring 6 is made of F91 steel paper, which can resist the erosion of oxygen in a high-temperature environment and is not prone to corrosion. The main steam valve disc snap ring 5 is made of GH901 superalloy. GH901 superalloy has relatively high yield strength and creep strength, improving the high-temperature performance, oxidation resistance, creep resistance, and fatigue resistance of the main steam valve disc snap ring 5.

[0022] In this embodiment, as Figure 2 shown, a third Stellite alloy bushing 16 is spray-welded on the inner surface of the main steam valve disc stop ring 6 to increase the structural strength inside the main steam valve disc stop ring 6.

[0023] In this embodiment, as Figure 1As shown, a ring groove is provided on the surface of the connecting part 9, and a regulating valve guide pin 7 is arranged inside the ring groove. The inner wall of the main steam valve disc stop is arranged in a stepped shape, and the main steam valve disc stop ring 6 is sleeved on the surface of the regulating valve guide pin 7. The regulating valve guide pin 7 is also made of GH901 superalloy, which is not easy to deform under high temperature and has a stable guiding effect.

[0024] In this embodiment, as Figure 1 shown, a sealing ring 14 is sleeved on the surface of the valve stem 4, and the sealing ring 14 abuts against the right end of the lower bushing 2 to strengthen the sealing effect of the lower bushing 2 and can scrape off some impurities.

[0025] In this embodiment, as Figure 1 shown, a sealing sleeve 15 is arranged on the inner wall of the sealing ring 8. The sealing sleeve 15 is sleeved on the surface of the main steam valve disc snap ring 5 to prevent steam leakage. The sealing sleeve 15 is fixed by an internal hexagonal screw and can be replaced.

[0026] Specifically, in use, the upper bushing 1 and the lower bushing 2 are spray-welded so that the first Stellite alloy bushing 10 and the second Stellite alloy bushing 11 are of an integral structure. The valve stem 4 moves in the first Stellite alloy bushing 10 and the second Stellite alloy bushing 11, and it is not easy to damage the first Stellite alloy bushing 10 and the second Stellite alloy bushing 11. The sealing ring 8 and the main steam valve disc snap ring 5 are strengthened in sealing performance by the sealing sleeve 15, and the sealing sleeve 15 is of a replaceable design, which is convenient for maintenance. The upper bushing 1, the lower bushing 2, and the sealing ring 8 are made of F92 alloy steel, the main steam valve disc stop ring 6 is made of F91 steel paper, and the regulating valve guide pin 7 and the main steam valve disc snap ring 5 are made of GH901 superalloy. The medium-pressure combined steam valve of the steam turbine is optimized in terms of material and structure, which can not only solve the defect of valve jamming but also control the investment in transformation costs, and the safety hazard of valve jamming is handled.

[0027] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A steam turbine medium-pressure combined valve anti-jamming structure, characterized in that: It comprises an upper bushing (1) and a lower bushing (2), wherein a first Stellite alloy bushing (10) and a second Stellite alloy bushing (11) are spray-welded inside the upper bushing (1) and the lower bushing (2) respectively; The upper bushing (1) and the lower bushing (2) are sleeved with a valve cover (3), the valve cover (3) is clamped by the upper bushing (1) and the lower bushing, and a sealing ring (8) is installed on the right side of the valve cover (3); A valve stem (4) is inserted into the first Stellite alloy bushing (10) and the second Stellite alloy bushing (11), and the right end of the valve stem (4) is provided with a connecting portion (9), and a main steam valve disc stop ring (6) is sleeved on the surface of the connecting portion (9), and a main steam valve disc retaining ring (5) is sleeved on the surface of the main steam valve disc stop ring (6), and the main steam valve disc retaining ring (5) is sealed and connected to the inner wall of the sealing ring (8).

2. The steam turbine intermediate pressure combined valve anti-jamming structure according to claim 1, characterized in that: A third Stellite alloy bushing (16) is spray-welded on the inner surface of the main steam valve disc stop ring (6).

3. The steam turbine intermediate pressure combined valve anti-jamming structure according to claim 1, characterized in that: The surface of the connecting portion (9) is provided with an annular groove, a regulating valve guide pin (7) is provided inside the annular groove, the main steam valve disc stop inner wall is arranged in a stepped shape, and the main steam valve disc stop ring (6) is sleeved on the surface of the regulating valve guide pin (7).

4. The steam turbine intermediate pressure combined valve anti-jamming structure according to claim 1, characterized in that: A sealing ring (14) is sleeved on the surface of the valve stem (4), and the sealing ring (14) is pressed against the right end of the lower bushing (2).

5. The steam turbine intermediate pressure combined valve anti-jamming structure according to claim 1, characterized in that: The inner wall of the sealing ring (8) is provided with a sealing sleeve (15), and the sealing sleeve (15) is sleeved on the surface of the main steam valve disc clamping ring (5).

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