Elastic sealing device for sealing horizontal split of steam turbine cylinder

Abstract

The utility model discloses an elastic sealing device for a horizontal split of a steam turbine cylinder. The elastic sealing device comprises a first elastic sealing ring and a second elastic sealing ring, the screws are used for fixing the first elastic sealing ring and the second elastic sealing ring in the threaded holes of the lower half part of the cylinder; a sealing groove is formed in the cylinder upper half; according to the design of the depth H of the sealing groove, when the upper half cylinder and the lower half cylinder of the air cylinder are closed, the first elastic sealing ring is compressed to 90%-95% of the original thickness, and pre-tightening sealing is formed; the inner side of the first elastic sealing ring and the inner side of the second elastic sealing ring make contact with the cylinder upper half to form a stepped sealing face used for triggering secondary sealing through pressure difference when a high-pressure working medium leaks. The sealing device can be applied to sealing of the horizontal split of the upper half and the lower half of the steam chamber of the steam turbine, internal leakage of a steam turbine set is reduced, the set efficiency is improved, the sealing device does not need to depend on tightening force for sealing, the good sealing effect can be achieved by means of self-weight press fit and internal and external pressure difference, and the use scene is wider.

Description

Technical Field

[0001] This utility model relates to the field of steam turbine cylinder sealing technology, and in particular to an elastic sealing device for sealing the horizontal split surface of a steam turbine cylinder. Background Technology

[0002] The turbine cylinder is a crucial component of a steam turbine. During the design process, steam often enters from the upper half of the cylinder through an opening at the split face into the lower half. The sealing performance of the mating surfaces of the upper and lower halves directly impacts the unit's thermal efficiency and operational safety and stability. Traditional sealing structures often employ multi-layer sealing rings or toothed gaskets. These structures work by gradually reducing pressure, ultimately relying on the tightening force between the upper and lower halves of the cylinder to prevent working fluid leakage. However, under high temperature and pressure conditions, or when the tightening force at the split face of the cylinder is insufficient, seal failure can easily occur, leading to steam leakage, reduced unit efficiency, and even affecting safe operation. Therefore, a sealing structure that can adapt to various complex operating conditions and possesses good elasticity and sealing performance is needed.

[0003] Currently, some sealing structures for the split surface of steam turbine cylinders are in use. For example, the utility model patent technology (publication number: CN 204402594 U) of Jinzhou Xinjinhua Machinery Manufacturing Co., Ltd. discloses a sealing structure for the split surface of steam turbine cylinders. By cooperating with two piston rings and the connecting cylinder, the leakage of the working fluid is reduced and the working fluid is depressurized. After depressurization, the small amount of working fluid that leaks is sealed by the tightness of the upper and lower halves of the cylinder. This type of sealing structure is simple and practical. However, for working fluids with high pressure and when the split surface of the cylinder does not have a certain tightness, this device cannot completely prevent the leakage of the working fluid. Utility Model Content

[0004] The purpose of this invention is to provide an elastic sealing device for horizontal split-face sealing of a steam turbine cylinder, thereby solving the aforementioned problems in the prior art.

[0005] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0006] An elastic sealing device for the horizontal split surface of a steam turbine cylinder, comprising:

[0007] First elastic sealing ring and second elastic sealing ring;

[0008] Screws are used to fix the first and second elastic sealing rings in the threaded holes in the lower half of the cylinder.

[0009] The upper half of the cylinder is provided with a sealing groove; the depth H of the sealing groove is designed such that when the upper and lower halves of the cylinder are closed, the first elastic sealing ring is compressed to 90%-95% of its original thickness, forming a pre-tight seal.

[0010] The inner sides of the first and second elastic sealing rings contact the upper half of the cylinder to form a stepped sealing surface, which is used to trigger a secondary seal by pressure difference when the high-pressure working fluid leaks.

[0011] In some specific embodiments, the thickness of the first elastic sealing ring is 2-5 mm, and its inner surface is provided with an annular groove with a groove width of 0.8-1.2 mm and a depth of 0.5-1 mm.

[0012] In some specific embodiments, the axial width of the second elastic sealing ring is smaller than that of the first elastic sealing ring, and the distance between the two is 3-6 mm, forming a buffer chamber.

[0013] In some specific embodiments, the number of screws is 12-20, evenly distributed along the horizontal split surface of the lower half of the cylinder, with a spacing of 50-80mm between adjacent screws.

[0014] In some specific embodiments, the first and second elastic sealing rings are made of GH4169 alloy and are coated with a high-temperature resistant ceramic coating with a coating thickness of 0.1-0.3 mm.

[0015] In some specific embodiments, the ceramic coating is a zirconia-based composite coating with a thermal conductivity ≤1.2W / (m·K) and a temperature resistance rating ≥800℃.

[0016] In some specific embodiments, the length of the screw thread is 1-2 mm longer than the depth of the mounting hole in the lower half of the cylinder, forming a redundant structure to prevent loosening.

[0017] In some specific embodiments, the buffer chamber is connected to an external pressure relief channel through a guide hole, the diameter of which is 2-3 mm.

[0018] The beneficial effects of this utility model are as follows: This utility model discloses an elastic sealing device for the horizontal split surface of a steam turbine cylinder, including a first elastic sealing ring and a second elastic sealing ring; multiple screws for fixing the first and second elastic sealing rings in threaded holes in the lower half of the cylinder; a sealing groove is provided in the upper half of the cylinder; the depth H of the sealing groove is designed such that when the upper and lower halves of the cylinder are closed, the first elastic sealing ring is compressed to 90%-95% of its original thickness, forming a pre-tight seal; the inner sides of the first and second elastic sealing rings contact the upper half of the cylinder to form a stepped sealing surface, which is used to trigger a secondary seal through pressure difference when the high-pressure working fluid leaks. Beneficial effects:

[0019] (1) This device solves the problem of working fluid leakage at the horizontal joint surface of the upper and lower cylinders of the steam turbine;

[0020] (2) This device can also be used for sealing the horizontal split surface of the upper and lower halves of the steam chamber of the steam turbine, reducing internal leakage of the steam turbine unit and improving the unit efficiency.

[0021] (3) This device does not require tightness to seal. It can achieve a good sealing effect by relying on its own weight and the pressure difference between the inside and outside, and has a wider range of applications.

[0022] (4) This device adopts a double-layer sealing structure, which can achieve continuous and efficient sealing. Attached Figure Description

[0023] Appendix Figure 1 This is a schematic diagram of the elastic sealing device for the horizontal split-face sealing of the steam turbine cylinder according to this utility model.

[0024] In the attached diagram, 1. First elastic sealing ring; 2. Second elastic sealing ring; 3. Screw; 4. Upper half of cylinder; 5. Lower half of cylinder; Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the scope of the present utility model.

[0026] Reference Figure 1 The elastic sealing device shown is for the horizontal split surface of a steam turbine cylinder, comprising:

[0027] First elastic sealing ring 1 and second elastic sealing ring 2;

[0028] Screw 3 is used to fix the first elastic sealing ring 1 and the second elastic sealing ring 2 in the threaded hole of the lower half of the cylinder 5;

[0029] The upper half of the cylinder 4 is provided with a sealing groove; the depth H of the sealing groove is designed such that when the upper and lower halves of the cylinder are closed, the first elastic sealing ring 1 is compressed to 90%-95% of its original thickness, forming a pre-tight seal.

[0030] The inner sides of the first elastic sealing ring 1 and the second elastic sealing ring 2 contact the upper half 4 of the cylinder to form a stepped sealing surface, which is used to trigger a secondary seal by pressure difference when the high-pressure working fluid leaks.

[0031] In this embodiment, the device comprises a first elastic sealing ring 1, a second elastic sealing ring 2, and screws 3 assembled together. The first elastic sealing ring 1 and the second elastic sealing ring 2 can be made of high-temperature and corrosion-resistant elastic sealing alloy materials, such as GH4169. Under cryogenic and high-temperature conditions, the performance is stable, the yield strength is high, and it can adapt well to high and low temperature working environments. At the same time, the good corrosion resistance ensures good and long-lasting sealing performance in saturated steam turbines. The good material plasticity and high strength properties ensure that the elastic sealing ring only needs a thickness of 1 to 3 mm to achieve continuous sealing performance under high pressure differential and high temperature environments.

[0032] In some specific embodiments, the thickness of the first elastic sealing ring 1 is 2-5mm, and its inner surface is provided with an annular groove with a groove width of 0.8-1.2mm and a depth of 0.5-1mm.

[0033] In some specific embodiments, the axial width of the second elastic sealing ring 2 is smaller than that of the first elastic sealing ring 1, and the distance between the two is 3-6 mm, forming a buffer chamber.

[0034] In some specific embodiments, the number of screws 3 is 12-20, which are evenly distributed along the horizontal split surface of the lower half of the cylinder 5, and the spacing between adjacent screws is 50-80mm.

[0035] In some specific embodiments, the first elastic sealing ring 1 and the second elastic sealing ring 2 are made of GH4169 alloy and are coated with a high-temperature resistant ceramic coating with a coating thickness of 0.1-0.3 mm.

[0036] In some specific embodiments, the depth H of the sealing groove is inversely proportional to the material hardness of the upper cylinder 4. When the Rockwell hardness of the material is ≥ HRC35, H = 3 ± 0.2 mm; when the hardness is < HRC35, H = 2.5 ± 0.2 mm.

[0037] In some specific embodiments, the elastic sealing device is also suitable for sealing the horizontal split surface of the steam chamber of a steam turbine and the bearing housing, and the sealing groove depth H is adjusted according to the thermal expansion coefficient of the sealed component.

[0038] In some specific embodiments, the ceramic coating is a zirconia-based composite coating with a thermal conductivity ≤1.2W / (m·K) and a temperature resistance rating ≥800℃.

[0039] In some specific embodiments, the thread length of screw 3 is 1-2 mm longer than the mounting hole depth of the lower half of cylinder 5, forming a redundant structure to prevent loosening.

[0040] In some specific embodiments, the buffer chamber is connected to an external pressure relief channel through a guide hole, the diameter of which is 2-3 mm.

[0041] Installation method: The first elastic sealing ring 1 and the second elastic sealing ring 2 are installed and pressed onto the lower half of the turbine cylinder 5 by tapping 12 to 20 threaded holes around the cylinder. A groove is cut into the upper half of the cylinder 4 to accommodate this elastic sealing device. By controlling the size of the groove depth H, it is ensured that after the upper and lower halves of the cylinder are closed, the weight of the upper half of the cylinder 4 keeps the first elastic sealing ring 1 in a slightly compressed state, thus ensuring a seal.

[0042] Sealing working principle: When the high-pressure working fluid flows from the upper half of the cylinder 4 through the flow channel to the lower half of the cylinder 5, a high-pressure side is formed in the inner chamber a of the first elastic sealing ring 1. The contact surface between the first elastic sealing ring 1 and the upper half of the cylinder 4 forms a sealing surface A. The higher the pressure, the better the seal. If a small leakage occurs at the first elastic sealing ring 1 after a long period of operation, the working fluid will be exposed from the sealing surface A into the chamber b. A pressure difference will be generated between the inner and outer sides of the second elastic sealing ring 2. The pressure difference will press the second elastic sealing ring 2 tightly onto the upper half of the cylinder 4, forming a sealing surface B, which will again prevent the leakage of the working fluid.

[0043] This device can prevent working fluid leakage under high pressure conditions and when the tightening force of the horizontal split surface of the turbine cylinder is insufficient. The first elastic sealing ring 1 forms a sealing surface through the pressure difference between the self-weight of the upper half of the cylinder 4 and the working fluid, and does not have high requirements for the tightening force of the horizontal split surface of the cylinder; the second elastic sealing ring 2 forms a seal through its own internal and external pressure difference, and also does not have high requirements for the tightening force of the horizontal split surface of the cylinder.

[0044] By adopting the above-disclosed technical solution of this utility model, the following beneficial effects are obtained:

[0045] This utility model discloses an elastic sealing device for the horizontal split surface of a steam turbine cylinder, including a first elastic sealing ring and a second elastic sealing ring; multiple screws for fixing the first and second elastic sealing rings in threaded holes in the lower half of the cylinder; a sealing groove is provided on the upper half of the cylinder; the depth H of the sealing groove is designed such that when the upper and lower halves of the cylinder are closed, the first elastic sealing ring is compressed to 90%-95% of its original thickness, forming a pre-tight seal; the inner sides of the first and second elastic sealing rings contact the upper half of the cylinder to form a stepped sealing surface, which is used to trigger a secondary seal through pressure difference when high-pressure working fluid leaks. Beneficial effects:

[0046] (1) This device solves the problem of working fluid leakage at the horizontal joint surface of the upper and lower cylinders of the steam turbine;

[0047] (2) This device can also be used for sealing the horizontal split surface of the upper and lower halves of the steam chamber of the steam turbine, reducing internal leakage of the steam turbine unit and improving the unit efficiency.

[0048] (3) This device does not require tightness to seal. It can achieve a good sealing effect by relying on its own weight and the pressure difference between the inside and outside, and has a wider range of applications.

[0049] (4) This device adopts a double-layer sealing structure, which can achieve continuous and efficient sealing.

[0050] (5) The size of the structure of this device can be changed according to the needs of the application scenario, which solves the problem of strict installation space requirements for conventional sealing types (for example, the toothed gasket sealing type is not suitable when the cylinder split surface opening is large, and it is difficult to guarantee the tightness requirements; for example, the inner and outer sealing ring plus sleeve sealing type is not suitable for small steam turbines with compact structure, where there is no space to install such a seal).

[0051] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. An elastomeric seal for a steam turbine casing horizontal split face seal, characterised in that, The utility model relates to a sealing structure of cylinder, which comprises: a first elastic sealing ring (1) and a second elastic sealing ring (2); a plurality of screws (3) for fixing the first elastic sealing ring (1) and the second elastic sealing ring (2) in threaded holes of a lower half of the cylinder (5); an upper half of the cylinder (4) is provided with a sealing groove; the depth H of the sealing groove is designed such that when the upper and lower halves of the cylinder are combined, the first elastic sealing ring (1) is compressed to 90%-95% of the original thickness, forming a pre-tightening seal; the inner sides of the first elastic sealing ring (1) and the second elastic sealing ring (2) are in contact with the upper half of the cylinder (4) to form a stepped sealing surface, which is used to trigger secondary sealing through pressure difference when high-pressure working medium leaks.

2. The elastomeric seal of claim 1, wherein The thickness of the first elastic sealing ring (1) is 2-5 mm, and the inner side surface thereof is provided with an annular groove with a width of 0.8-1.2 mm and a depth of 0.5-1 mm.

3. The elastomeric seal of claim 1, wherein The axial width of the second elastic sealing ring (2) is smaller than that of the first elastic sealing ring (1), and the spacing between the two is 3-6 mm, forming a buffer chamber.

4. The elastomeric seal of claim 1, wherein The number of the screws (3) is 12-20, which are uniformly distributed along the horizontal center plane of the lower half of the cylinder (5) with a spacing of 50-80 mm between adjacent screws.

5. The elastomeric seal of claim 1, wherein The first elastic sealing ring (1) and the second elastic sealing ring (2) are made of GH4169 alloy and coated with a high-temperature-resistant ceramic coating with a thickness of 0.1-0.3 mm.

6. The elastomeric seal of claim 5, wherein The ceramic coating is a zirconia-based composite coating with a thermal conductivity of ≤1.2 W / (m·K) and a temperature resistance grade of ≥800℃.

7. The elastomeric seal of claim 4, wherein The length of the threaded section of the screw (3) is 1-2 mm longer than the depth of the mounting hole of the lower half of the cylinder (5), forming an anti-loosening redundant structure.

8. The elastomeric seal of claim 3, wherein The buffer chamber is in communication with an external pressure relief channel through a flow guide hole with a diameter of 2-3 mm.

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