A split face seal structure in a steam turbine

Abstract

The utility model discloses a middle split surface sealing structure of steam turbine belongs to steam turbine equipment technical field. The structure includes upper cylinder body, lower cylinder body, and sets up the sealing groove on the lower cylinder surface of lower cylinder body, and sets up the sealing key in the groove, and is equipped with support spring between sealing key and sealing groove bottom. When assembling, the upper cylinder body compresses the support spring and forms the initial sealing of sealing key compression. When operating, the elasticity of support spring can dynamically compensate the clearance change between middle split surface, and keeps sealing pressure. The utility model discloses the floating sealing key structure of spring support, has realized the reliable dynamic sealing of middle split surface, has solved the problem that traditional sealing mode is poor in adaptability, and the maintenance is inconvenient, has the advantages such as reliable sealing, long life, and convenient maintenance.

Description

Technical Field

[0001] This utility model relates to the field of steam turbine equipment technology, and in particular to a steam turbine split-face sealing structure. Background Technology

[0002] The sealing of the split surface of the turbine cylinder is crucial for its safe, stable, and efficient operation. During unit operation, the cylinder and its connecting bolts undergo thermal expansion and deformation under the action of high-temperature and high-pressure steam, which may lead to gaps in the split surface and cause steam leakage. Steam leakage not only reduces unit efficiency and affects economics, but may also erode and damage the mating surfaces, and even cause safety accidents.

[0003] In existing technologies, methods such as improving machining accuracy, using high-strength bolts to apply huge preload, or applying high-temperature sealant are commonly used to ensure sealing. However, these methods all have limitations: improving machining accuracy and applying huge preload significantly increases manufacturing costs and assembly difficulty, and their sealing effect may still decrease under high-parameter operating conditions due to deformation inconsistencies; sealant suffers from aging failure, difficulty in disassembly, and troublesome residue cleaning, which is not conducive to rapid inspection and maintenance of the unit. In addition, traditional rigid gaskets or metal sealing strips are difficult to dynamically compensate for real-time changes in the gap between the mating surfaces during unit start-up and shutdown and operation under varying conditions, and the reliability of the seal needs to be improved. Utility Model Content

[0004] The purpose of this invention is to provide a turbine split-face sealing structure, which aims to solve the technical problems of existing technologies such as difficulty in dynamically compensating for changes in the split-face gap, insufficient sealing reliability, and inconvenient maintenance.

[0005] This utility model is achieved using the following technical solution: a split-face sealing structure for a steam turbine, comprising an upper cylinder and a lower cylinder, wherein the upper cylinder and the lower cylinder are connected to form a steam turbine cylinder, characterized in that: at least one sealing groove is provided on the lower cylinder surface of the lower cylinder, a sealing key is provided in the sealing groove, and a support spring is provided between the sealing key and the bottom of the sealing groove, the support spring being used to pre-tighten the sealing key toward the upper cylinder, so that the upper surface of the sealing key is in sealing contact with the lower end face of the upper cylinder.

[0006] Furthermore, the sealing groove is a rectangular groove, and it is evenly distributed circumferentially along the mid-section.

[0007] Furthermore, the sealing key is a rectangular cross-section elongated metal piece, and the width of the sealing key is smaller than the width of the sealing groove, and the height is smaller than the depth of the sealing groove.

[0008] Furthermore, the sealing key is placed in the sealing groove with a clearance fit, and a gap is left between the lower surface of the sealing key and the bottom of the sealing groove.

[0009] Furthermore, the support spring is a serpentine spring.

[0010] Furthermore, the upper surface of the sealing key is coated with a high-temperature sealing coating.

[0011] Furthermore, the upper cylinder and the lower cylinder are connected by bolts. When the bolts are tightened, the upper cylinder presses against the sealing key and compresses the support spring to form a sealing pressure.

[0012] The beneficial effects of the turbine split-face sealing structure described in this utility model include: By providing continuous elastic preload through the support spring, the turbine can automatically and in real time compensate for the changes in the mid-plane gap caused by thermal expansion and contraction during start-up, shutdown, and operation under varying conditions, thus maintaining an effective sealing pressure, effectively preventing steam leakage, and ensuring high sealing reliability.

[0013] The sealing key can float slightly under the action of the supporting spring, which can automatically adapt to the unevenness of the mating surface, avoid local stress concentration, reduce the squeezing damage to the cylinder mating surface, and extend the service life of the equipment.

[0014] When the unit is shut down and the upper cylinder is disassembled, the support spring can automatically push the sealing key out of the sealing groove, making it easy to observe the condition of the sealing key and replace it. It can automatically reset during assembly, simplifying the maintenance process and improving maintenance efficiency.

[0015] This compact structure is easy to manufacture and install, and is particularly suitable for high-temperature and high-pressure operating conditions, effectively improving the safety and economy of steam turbine operation. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of a split-face sealing structure for a steam turbine; In the diagram: 1. Upper cylinder block; 2. Lower cylinder block; 3. Lower cylinder surface; 4. Sealing groove; 5. Sealing key; 6. Support spring. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0019] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention. Example

[0020] like Figure 1 As shown, this embodiment provides a turbine split-face sealing structure, mainly composed of an upper cylinder body 1, a lower cylinder body 2, a lower cylinder surface 3, sealing grooves 4, sealing keys 5, and supporting springs 6. The upper cylinder body 1 and the lower cylinder body 2 are connected by bolts to form a turbine cylinder, wherein the upper end face of the lower cylinder body 2 is the lower cylinder surface 3, and the lower cylinder surface 3 and the lower end face of the upper cylinder body 1 together form the split-face joint. Multiple sealing grooves 4 are machined on the lower cylinder surface 3. The sealing grooves 4 are rectangular grooves, evenly distributed along the circumference of the split-face, and each sealing groove 4 has a spring mounting hole at its bottom.

[0021] The sealing key 5 is a rectangular strip-shaped metal component made of high-temperature alloy steel. Its width is slightly smaller than the width of the sealing groove 4, and its height is slightly smaller than the depth of the sealing groove 4. The sealing key 5 is placed within the sealing groove 4 with a clearance fit, leaving a gap between the lower surface of the sealing key 5 and the bottom of the sealing groove 4. Multiple sets of support springs 6, which are serpentine springs, are installed below each sealing key 5. The support springs 6 are fixed to the bottom of the sealing groove 4 through spring mounting holes and contact the lower surface of the sealing key 5, thereby pre-tightening the sealing key 5 upwards, making the upper surface of the sealing key 5 slightly higher than the lower cylinder surface 3.

[0022] When the upper cylinder 1 and lower cylinder 2 are fastened together with bolts, the lower end face of the upper cylinder 1 presses against the upper surface of the sealing key 5, forcing the sealing key 5 to move downwards and compressing the support spring 6. The compressed support spring 6 generates a rebound force, which acts on the sealing key 5, creating a tight contact between the sealing key 5 and the lower end face of the upper cylinder 1. Both the upper and lower surfaces of the sealing key 5 are coated with a high-temperature sealing coating to enhance the sealing effect.

[0023] During turbine operation, temperature and pressure changes cause thermal expansion and mechanical deformation in the upper cylinder 1 and lower cylinder 2. The support spring 6 automatically compensates for changes in the gap between the mating surfaces: when the gap increases, the support spring 6 pushes the sealing key 5 upwards to maintain contact pressure with the upper cylinder 1; when the gap decreases, the upper cylinder 1 further compresses the sealing key 5, and the support spring 6 absorbs the excess displacement, preventing the sealing key 5 from being damaged due to excessive pressure. This dynamic compensation mechanism ensures the reliability of the seal.

[0024] Furthermore, the sealing key 5 features a self-aligning installation method. During assembly, the sealing key 5 can slightly float under the support spring 6, automatically adjusting its position to adapt to the unevenness of the mating surface. The side of the sealing groove 4 is designed with guide bevels to facilitate the insertion and alignment of the sealing key 5. The two ends of the sealing key 5 are beveled to avoid interference with the groove opening.

[0025] When the steam turbine is shut down for maintenance, the connecting bolts are loosened, and the upper cylinder 1 is lifted. The support spring 6 pushes the sealing key 5 out of the sealing groove 4, facilitating inspection and replacement of the sealing key 5. During reassembly, the sealing key 5 automatically resets under the spring force, requiring no manual adjustment.

[0026] Through the above structural design, this sealing structure exhibits significant technical advantages. First, the continuous preload provided by the support spring 6 effectively compensates for changes in the mating surface gap under hot conditions, preventing steam leakage and improving the efficiency and economy of the turbine. Second, the floating design of the sealing key 5 avoids localized stress concentration, reduces wear and plastic deformation of the mating surface, and extends equipment life. Third, the spring support structure allows the sealing key 5 to automatically pop out during disassembly and assembly, simplifying the maintenance process and reducing maintenance costs. Finally, this sealing structure is suitable for high-temperature and high-pressure environments, with stable and reliable sealing performance, reducing the risk of unplanned downtime. Therefore, this solution demonstrates superiority in terms of safety, lifespan, and maintainability.

[0027] The above embodiments describe the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Modifications and variations made by those skilled in the art without departing from the spirit and scope of this utility model should be protected within the scope of the appended claims.

Claims

1. A split-face sealing structure for a steam turbine, comprising an upper cylinder body (1) and a lower cylinder body (2), wherein the upper cylinder body (1) and the lower cylinder body (2) are connected to form a steam turbine cylinder, characterized in that: At least one sealing groove (4) is provided on the lower cylinder surface (3) of the lower cylinder body (2). A sealing key (5) is provided in the sealing groove (4). A support spring (6) is provided between the sealing key (5) and the bottom of the sealing groove (4). The support spring (6) is used to pre-tighten the sealing key (5) towards the upper cylinder body (1) so that the upper surface of the sealing key (5) is in sealing contact with the lower end face of the upper cylinder body (1).

2. The turbine split-face sealing structure according to claim 1, characterized in that, The sealing groove (4) is a rectangular groove, and is evenly distributed circumferentially along the mid-section.

3. The turbine split-face sealing structure according to claim 1, characterized in that, The sealing key (5) is a rectangular cross-section strip-shaped metal piece. The width of the sealing key (5) is smaller than the width of the sealing groove (4), and the height is smaller than the depth of the sealing groove (4).

4. The turbine split-face sealing structure according to claim 1, characterized in that, The sealing key (5) is placed in the sealing groove (4) with a clearance fit, and a gap is left between the lower surface of the sealing key (5) and the bottom of the sealing groove (4).

5. The turbine split-face sealing structure according to claim 1, characterized in that, The support spring (6) is a serpentine spring.

6. The turbine split-face sealing structure according to claim 1, characterized in that, The upper surface of the sealing key (5) is coated with a high-temperature sealing coating.

7. The turbine split-face sealing structure according to claim 1, characterized in that, The upper cylinder (1) and the lower cylinder (2) are connected by bolts. When the bolts are tightened, the upper cylinder (1) presses against the sealing key (5) and compresses the support spring (6) to form a sealing pressure.

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