Hydrogen seal for a generator

Abstract

The application discloses a hydrogen sealing structure of a generator, which comprises an end cover, a transition ring and a sealing seat, rubber plates are arranged on the vertical joint surfaces of the end cover and the transition ring and the vertical joint surfaces of the transition ring and the sealing seat, horizontal surface oil grooves in communication are arranged on the horizontal joint surfaces of the transition ring and the sealing seat, three vertical surface circumferential oil grooves are arranged, one is arranged on the vertical joint surface of the end cover and the transition ring and is located on the transition ring and in communication with the horizontal surface oil groove on the transition ring, one is arranged on the vertical joint surface of the transition ring and the sealing seat and is located on the transition ring and in communication with the horizontal surface oil groove on the transition ring, and one is arranged on the vertical joint surface of the transition ring and the sealing seat and is located on the sealing seat and in communication with the horizontal surface oil groove on the sealing seat. The sealing structure realizes full-path sealing from the design source, blocks all paths of hydrogen leakage, eliminates the risk of hydrogen leakage and improves the reliability of the generator sealing.

Description

Technical Field

[0001] This invention relates to a hydrogen sealing structure for a generator, specifically a sealing structure in a hydrogen-cooled generator to prevent hydrogen leakage, and belongs to the field of gas sealing technology for steam turbine generators. Background Technology

[0002] Hydrogen-cooled generators require a dedicated gas supply system to supply the generator with hydrogen and air and replace these two gases. During the operation of the generator, hydrogen inside the casing may leak into the air through the generator's end cover, transition ring, and sealing seat, causing safety hazards.

[0003] Existing hydrogen-cooled generators use an oil-sealing system to seal the mating surfaces, such as... Figure 1 As shown, the mating surfaces (vertical mating surfaces) of the end cover and transition ring of the hydrogen-cooled generator, as well as the mating surfaces (vertical mating surfaces) of the transition ring and sealing seat, are sealed with rubber plates. The horizontal mating surfaces of the transition ring and sealing seat are sealed with sealing oil, and the horizontal mating surface of the end cover is sealed with a sealing strip. Hydrogen leakage from the generator mainly occurs through two paths: the horizontal mating surfaces and the vertical mating surfaces between the connecting parts. However, existing technology still has limitations, with two main risks of hydrogen leakage:

[0004] (1) Risk of air leakage caused by deformation of steel parts or aging of rubber parts:

[0005] The generator end cover and transition ring, and the transition ring and sealing seat are assembled together by rubber plates. The rubber plates are used for gas sealing by their elasticity and the compression during installation. However, after the generator set has been running for a long time, the rubber plates will age, and the end cover, transition ring and sealing seat will deform, resulting in the failure of the horizontal or vertical sealing and leakage.

[0006] (2) Risk of leakage due to installation uncertainty: The horizontal sealing strip of the end cap is seamlessly connected to the rubber plate by compression after the upper and lower half end caps and transition ring are closed, which places high demands on the installation of the sealing strip. However, in actual installation, the sealing strip may have problems such as displacement, insufficient or excessive end face protrusion, and excessive end face flatness. This results in insufficient or uneven compression of the sealing strip, creating gaps. As a result, the sealing path at the contact point between the two parts is discontinuous, and hydrogen may leak to the air side of the low-pressure area through the gap, resulting in an unsatisfactory hydrogen sealing effect.

[0007] The invention patent with publication number CN106787374A discloses a full-path sealing structure and assembly method for a steam turbine generator. This patent mainly addresses the sealing reliability of the steam turbine generator at the horizontal joint surface during operation. After the transition ring, end cover, and sealing seat are assembled in place, the first sealing strip forms a sealing structure with the first branch oil passage and the sealing plate, and the second sealing strip forms a sealing structure with the second branch oil passage and the sealing plate, thereby enabling the steam turbine generator to form a fully closed sealing structure at the horizontal joint surface. This can fully guarantee the barrier between the hydrogen inside the steam turbine generator and the air outside the steam turbine generator. However, this patent still does not solve the leakage caused by the failure of the vertical surface seal. Summary of the Invention

[0008] The purpose of this invention is to provide a hydrogen sealing structure for a generator. This sealing structure uses a combination of horizontal oil grooves and vertical circumferential oil grooves to achieve a complete seal between the generator end cover and the transition ring, and between the transition ring and the sealing seat, on both horizontal and vertical planes. This can effectively solve the problem of leakage caused by the failure of the horizontal or vertical sealing due to the aging of the rubber plate or structural deformation after the generator has been running for a long time.

[0009] This invention is achieved through the following technical solution: a generator hydrogen sealing structure, comprising an end cover, a transition ring, and a sealing seat. Rubber plates are provided on the vertical mating surfaces of the end cover and the transition ring, and on the vertical mating surfaces of the transition ring and the sealing seat. A horizontal oil groove is provided on the horizontal mating surfaces of the transition ring and the sealing seat. The structure also includes a vertical circumferential oil groove, which comprises at least one of the following three structures:

[0010] Ⅰ. Located on the vertical mating surface between the end cap and the transition ring, situated on the transition ring and connected to the horizontal oil groove on the transition ring;

[0011] II. Located on the vertical mating surface between the transition ring and the sealing seat, situated on the transition ring and connected to the horizontal oil groove on the transition ring;

[0012] Ⅲ. Located on the vertical mating surface of the transition ring and the sealing seat, situated on the sealing seat and connected to the horizontal oil groove on the sealing seat.

[0013] Sealing oil is injected into both the vertical circumferential oil groove and the vertical circumferential oil groove.

[0014] An opening for injecting sealing oil is provided on the rubber plate on the mating surface of the transition ring and the sealing seat.

[0015] A sealing strip groove and a horizontal glue injection groove are respectively opened on the end cap. The sealing strip groove is located on the vertical mating surface between the end cap and the transition ring, and the horizontal glue injection groove is located on the horizontal mating surface of the end cap. Sealant is injected into the horizontal glue injection groove, and a sealing strip is embedded in the sealing strip groove. The sealant and the sealing strip are seamlessly connected.

[0016] A circumferential glue injection groove and a horizontal glue injection groove are respectively provided on the end cap. The circumferential glue injection groove is located on the vertical mating surface between the end cap and the transition ring, and the horizontal glue injection groove is located on the horizontal mating surface of the end cap and is connected to the circumferential glue injection groove.

[0017] Both the circumferential and horizontal injection grooves are filled with sealant.

[0018] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0019] (1) The present invention adds a vertical circumferential oil groove to the vertical mating surface of the existing end cap and transition ring, and the vertical mating surface of the transition ring and sealing seat. The vertical circumferential oil groove is connected with the horizontal oil groove, thereby achieving sealing between the end cap and transition ring, and between the transition ring and sealing seat on the horizontal and vertical surfaces.

[0020] (2) The present invention further achieves sealing between the end cap and the transition ring on the horizontal and vertical planes by designing a through circumferential glue injection groove and a horizontal glue injection groove on the end cap.

[0021] In summary, this invention provides comprehensive sealing between the end cap and the transition ring, and between the transition ring and the sealing seat in both horizontal and vertical planes. It achieves full-path sealing from the design source, blocking all paths of hydrogen leakage, eliminating the risk of hydrogen leakage, and improving the reliability of generator sealing. It can be used to solve the problem of unsatisfactory hydrogen sealing effect and hydrogen leakage caused by the aging of rubber plates, deformation of end caps, transition rings and sealing seats, and discontinuous sealing paths of sealing strips in existing sealing structures. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the hydrogen sealing structure of an existing generator.

[0023] Figure 2 This is a schematic diagram of the structure of the present invention (I).

[0024] Figure 3 for Figure 2 The structural diagram of A is shown.

[0025] Figure 4 This is a schematic diagram (II) of the structure of the present invention.

[0026] Among them, 1—end cap, 2—transition ring, 3—sealing seat, 4—rubber plate, 5—horizontal oil groove, 6—vertical circumferential oil groove, 7—sealing oil, 8—sealing strip groove, 9—horizontal glue injection groove, 10—sealing glue, 11—sealing strip, 12—circumferential glue injection groove, 13—rotating shaft, 14—horizontal sealing strip. Detailed Implementation

[0027] The present invention will be further described in detail below with reference to embodiments, but the implementation of the present invention is not limited thereto.

[0028] Example:

[0029] This embodiment is a hydrogen sealing structure for a generator, which is suitable for effectively sealing the mating surfaces between the end cover 1, transition ring 2, and sealing seat 3 of a hydrogen-cooled generator. It can reduce the risk of hydrogen leakage, reduce the amount of hydrogen leakage from the turbine generator, thereby improving the safety performance of the equipment and reducing safety hazards.

[0030] Figure 1 This design incorporates a sealing structure for the mating surfaces of the end cover 1, transition ring 2, and sealing seat 3 of an existing steam turbine generator. The end cover 1, transition ring 2, and sealing seat 3 are fitted and sleeved onto the rotating shaft 13. The vertical mating surfaces of the end cover 1 and transition ring 2, and the vertical mating surfaces of the transition ring 2 and sealing seat 3, are sealed by rubber plates 4. The horizontal mating surfaces of the transition ring 2 and sealing seat 3 are sealed by horizontal oil grooves 5. However, two hydrogen leakage risks still exist: first, hydrogen leakage due to steel deformation or rubber aging causing failure of the horizontal or vertical sealing surfaces; second, hydrogen leakage due to gaps in the installation of the horizontal sealing strip 14 of the end cover 1. See [link to relevant documentation] for the hydrogen leakage path. Figure 1 The arrow symbol is indicated by a dashed line.

[0031] To address these two hydrogen leakage risks and ensure the reliability of the turbine generator seal, in a specific embodiment, for the first hydrogen leakage risk, continuous pressurized oil is introduced at the contact point between the two components to achieve a full-path seal. Specifically, based on the original design of the transition ring 2 and the sealing seat 3, three vertical circumferential oil grooves 6 are added. (See [reference]). Figure 2 , Figure 3 As shown, the structure and positional relationship of the three vertical circumferential oil grooves 6 are as follows:

[0032] Ⅰ. Located on the vertical mating surface of the end cap 1 and the transition ring 2, situated on the transition ring 2 and connected to the horizontal oil groove 5 on the transition ring 2;

[0033] II. Located on the vertical mating surface of the transition ring 2 and the sealing seat 3, situated on the transition ring 2 and connected to the horizontal oil groove 5 on the transition ring 2;

[0034] III. Located on the vertical mating surface of the transition ring 2 and the sealing seat 3, situated on the sealing seat 3 and connected to the horizontal oil groove 5 on the sealing seat 3.

[0035] When the generator oil sealing system is running, the sealing oil 7 fills the horizontal oil groove 5 and the vertical circumferential oil groove 6 on the transition ring 2 and the sealing seat 3 through the opening on the rubber plate 4. The sealing oil 7 completely isolates the hydrogen in the high-pressure area from the air in the low-pressure area, achieving a seamless connection and realizing a complete seal between the horizontal mating surface and the vertical mating surface of the transition ring 2 and the sealing seat 3.

[0036] Regarding the second risk of hydrogen leakage, such as Figure 2 As shown, a sealing groove 8 and a horizontal glue injection groove 9 are respectively opened on the end cap 1. The sealing groove 8 is located on the vertical mating surface of the end cap 1 and the transition ring 2. A (compression type) sealing strip 11 is embedded in the sealing groove 8. The horizontal glue injection groove 9 is located on the horizontal mating surface of the end cap 1 and is close to the center of the end cap 1. Sealant 10 is injected into the horizontal glue injection groove 9. The sealant 10 is seamlessly connected to the sealing strip 11, thereby achieving sealing of the horizontal mating surface of the end cap 1 and the vertical mating surface of the end cap 1 and the transition ring 2. The sealant 10 has the characteristic of good fluidity. In this embodiment, it is used to replace the existing horizontal surface sealing strip 14 of the upper and lower half end caps, which can solve the influence of the shape and size of the end face of the horizontal surface sealing strip 14 near the transition ring 2 on the sealing effect.

[0037] Furthermore, to ensure air venting during the injection of sealant 10, the horizontal injection groove 9 is as follows: Figure 2 As shown, two horizontal injection grooves 9 are provided, with an elliptical groove at the intersection of the two grooves. During injection, the sealant 10 is injected through one of the horizontal injection grooves 9. After reaching the elliptical groove, the injection continues, and the sealant 10 returns through the other horizontal injection groove 9, ensuring a smooth injection process and facilitating air venting during injection.

[0038] Alternatively, in another specific embodiment, a different improved structure can be used to address hydrogen leakage risk two, such as... Figure 4 As shown, a circumferential glue injection groove 12 and a horizontal glue injection groove 9 are respectively opened on the end cap 1. The circumferential glue injection groove 12 is located on the vertical mating surface of the end cap 1 and the transition ring 2. The horizontal glue injection groove 9 is located on the horizontal mating surface of the end cap 1 and is connected to the circumferential glue injection groove 12. By injecting sealant 10 into the horizontal glue injection groove 9 and the circumferential glue injection groove 12, the horizontal mating surface and the vertical mating surface of the end cap 1 are sealed. That is, the overall sealing of the end cap 1 and the end face of the transition ring 2 is achieved by the cooperation of the horizontal glue injection groove 9 and the circumferential glue injection groove 12.

[0039] Furthermore, a gas leak detector was used to... Figure 1 , Figure 2 , Figure 4 The structure shown was used to detect hydrogen leaks, and the detection results are shown in Table 1 below.

[0040] Table 1

[0041]

[0042] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A hydrogen sealing structure for a generator, comprising an end cap (1), a transition ring (2), and a sealing seat (3), wherein rubber plates (4) are provided on the vertical mating surfaces of the end cap (1) and the transition ring (2) and the vertical mating surfaces of the transition ring (2) and the sealing seat (3), and horizontal oil grooves (5) are provided on the horizontal mating surfaces of the transition ring (2) and the sealing seat (3), characterized in that: It also includes a vertical circumferential oil groove (6), which includes at least one of the following three structures: Ⅰ. Located on the vertical mating surface of the end cap (1) and the transition ring (2), located on the transition ring (2) and connected to the horizontal oil groove (5) on the transition ring (2); II. Located on the vertical mating surface of the transition ring (2) and the sealing seat (3), it is located on the transition ring (2) and connected to the horizontal oil groove (5) on the transition ring (2); Ⅲ. Located on the vertical mating surface of the transition ring (2) and the sealing seat (3), it is located on the sealing seat (3) and communicates with the horizontal oil groove (5) on the sealing seat (3).

2. The generator hydrogen sealing structure according to claim 1, characterized in that: Sealing oil (7) is injected into both the vertical circumferential oil groove (6) and the vertical circumferential oil groove (6).

3. The generator hydrogen sealing structure according to claim 2, characterized in that: An opening for injecting sealing oil (7) is provided on the rubber plate (4) on the perpendicular mating surface of the transition ring (2) and the sealing seat (3).

4. The generator hydrogen sealing structure according to claim 1, characterized in that: A sealing groove (8) and a horizontal glue injection groove (9) are respectively opened on the end cap (1). The sealing groove (8) is located on the vertical mating surface of the end cap (1) and the transition ring (2). The horizontal glue injection groove (9) is located on the horizontal mating surface of the end cap (1). Sealant (10) is injected into the horizontal glue injection groove (9). A sealing strip (11) is embedded in the sealing groove (8). The sealant (10) and the sealing strip (11) are seamlessly connected.

5. The generator hydrogen sealing structure according to claim 1, characterized in that: A circumferential glue injection groove (12) and a horizontal glue injection groove (9) are respectively opened on the end cap (1). The circumferential glue injection groove (12) is located on the vertical mating surface between the end cap (1) and the transition ring (2), and the horizontal glue injection groove (9) is located on the horizontal mating surface of the end cap (1) and is connected to the circumferential glue injection groove (12).

6. The generator hydrogen sealing structure according to claim 5, characterized in that: Both the circumferential injection groove (12) and the horizontal injection groove (9) are filled with sealant (10).

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