Adaptive sealing butt joint structure suitable for high parameter main steam pipeline

Abstract

The present application relates to the technical field of steam turbine, and provides a self-adaptive sealing butt joint structure suitable for high-parameter main steam pipeline, which can adapt to a certain opening amount generated in the pipeline operation or installation process, and meanwhile, the special double-sided sealing structure can ensure that one side of the sealing surface normally works in the pipeline operation, and allows a certain displacement of the flange sealing surface in the pipeline operation. Meanwhile, since the structure can isolate the main steam pipeline sealing stress from the main steam pipeline welding or operation stress, the requirements for the number and specifications of the pipeline flange bolts can be reduced, and the structural cost is reduced. The present application well solves the steam leakage problem caused by the welding deformation and thermal deformation of the high-parameter main steam pipeline flange, and provides a new solution for the main steam pipeline sealing problem caused by the continuous improvement of the main steam parameters in the industrial turbine field.

Description

Technical Field

[0001] This invention relates to the field of steam turbine technology, and in particular to an adaptive sealing docking structure suitable for high-parameter main steam pipelines. Background Technology

[0002] In the field of industrial turbines, steam turbines generally adopt nozzle regulation due to the wide load and multi-condition operation requirements of their units. Therefore, the nozzle group corresponding to the upper half of the cylinder needs to be guided to the upper half of the cylinder through the high-pressure steam pipe. For the convenience of unit installation and maintenance, the steam pipe needs to be designed with a flange connection structure at the split surface between the upper and lower cylinders.

[0003] In recent years, with the increasing demands for unit performance in the industry, the main steam parameters of steam turbines in the industrial turbine field have been continuously improved, leading to a continuous increase in the wall thickness of high-pressure steam pipes. The increased rigidity of the high-pressure steam pipes means that they no longer have the ability to compensate for deformation under low rigidity. When welding deformation and thermal deformation during operation cannot be well absorbed by the steam pipe itself, the stress in this part will inevitably be transferred to the flange connection with the weakest rigidity during operation, causing the flange sealing surface to open and form an internal and external through channel, resulting in steam leakage. In addition, there are additional vibrations and alternating hot and cold temperatures during pipeline operation, which can also cause momentary gaps in the sealing surface, resulting in temporary steam leakage. The characteristics of the gasket determine that once steam leakage occurs, the high-speed jet of steam will damage the gasket. Even if the gap disappears later, the seal cannot be restored properly due to the damage to the gasket.

[0004] Leakage in the high-pressure steam pipe flange during unit operation not only affects the plant environment and unit operating efficiency but also poses a significant threat to the safety of inspection personnel. The key to solving the problem of steam leakage in the high-pressure steam pipe flange lies in addressing the reduced deformation compensation capacity of the high-pressure steam pipe due to increased pipe thickness, while simultaneously mitigating the increased cost of high-pressure steam pipe flange connections caused by increased main steam volume. Summary of the Invention

[0005] In view of the shortcomings of the prior art described above, the technical problem to be solved by the present invention is to provide an adaptive sealing docking structure suitable for high-parameter main steam pipelines, which can adapt to the misalignment deformation of the pipeline caused by installation or operation and the changes in the upper and lower displacement of the sealing surface during operation.

[0006] To address the aforementioned technical problem, this invention provides an adaptive sealing connection structure suitable for high-parameter main steam pipelines, comprising:

[0007] The lower connector includes a lower pipe section and a lower flange formed on the outer peripheral wall of the lower pipe section. The pipe cavity of the lower pipe section includes a large-diameter hole and a small-diameter hole that are axially connected. A closely fitting inner spherical surface is formed at the shoulder of the hole between the large-diameter hole and the small-diameter hole.

[0008] The upper connector includes an upper pipe section and an upper flange that abuts against the upper pipe section. The bottom end of the upper pipe section forms a tight outer spherical surface. The bottom end of the upper pipe section is inserted into the large diameter hole so that a sealing fit is formed between the tight outer spherical surface and the tight inner spherical surface. The outer peripheral wall of the upper pipe section located in the large diameter hole is provided with a positive sealing groove and a reverse sealing groove. The outer peripheral wall of the upper pipe section located outside the large diameter hole has an annular protrusion. The side of the annular protrusion facing the lower connector forms abutting outer spherical surface. The upper flange has a flange center hole that allows the upper pipe section to pass through with a gap. The side of the upper flange facing the lower connector forms abutting inner spherical surface. A compression fit is formed between the abutting inner spherical surface and the abutting outer spherical surface.

[0009] A bidirectional sealing assembly includes a forward seal, a reverse seal, and a reverse pressure ring assembly. The forward seal is embedded in the forward sealing groove and seals against the shoulder of the hole. The reverse seal is located in the reverse sealing groove and seals against the wall of the large-diameter hole. The reverse pressure ring assembly is detachably mounted on the lower pipe or lower flange and blocks the reverse seal to confine it within the large-diameter hole.

[0010] The connecting components are detachably connected to the lower flange and the upper flange respectively, so that the lower flange and the upper flange can be brought closer together.

[0011] The lower pipe section and / or upper pipe section are used to connect to the high-parameter main steam pipeline.

[0012] Preferably, the reverse pressure ring assembly includes a ring-shaped clamping flange, which is sleeved on the upper pipe and mounted on the lower pipe or lower flange by clamping bolts. The inner periphery of the clamping flange protrudes along its own axis to form an annular locking protrusion, which extends into the large-diameter hole and blocks the reverse seal.

[0013] Preferably, the forward sealing groove or the reverse sealing groove has an annular stepped structure.

[0014] Preferably, the connecting assembly includes a flange bolt and a flange nut, the bottom end of the flange bolt is threaded to the lower flange, the top end of the flange bolt passes through the upper flange, and the flange nut is threaded to the top end of the flange bolt and is pressed against the upper flange.

[0015] Preferably, the connecting assembly further includes a limiting sleeve, which is fitted onto the flange bolt with a gap and is clamped between the lower flange and the upper flange.

[0016] Preferably, the forward seal is a single sealing ring, and the reverse seal is formed by stacking multiple sealing rings.

[0017] Preferably, the large-diameter hole has a stress relief groove on its wall, which is located between the positive sealing groove and the negative sealing groove.

[0018] Preferably, the lower connector is provided with a pressure monitoring hole, which is connected to the stress relief groove.

[0019] Preferably, a pressure sensor is provided inside the pressure monitoring port.

[0020] Preferably, the lower connector is provided with a steam guide channel, which is connected to the stress relief groove and to a steam exhaust area located outside the plant.

[0021] As described above, the adaptive sealing and docking structure of the present invention, applicable to high-parameter main steam pipelines, has the following beneficial effects: the tight-fitting outer spherical surface at the bottom of the upper pipe section and the tight-fitting inner spherical surface of the lower connector are in contact with each other. When the upper flange gradually approaches the lower flange through the connecting assembly, the abutting inner spherical surface of the large flange adaptively transmits pressure to the abutting outer spherical surface of the annular protrusion of the upper pipe section, and finally to the tight-fitting outer spherical surface at the bottom of the upper pipe section through the pipe wall. This generates a certain sealing stress between the spherical surface at the bottom of the upper pipe section and the tight-fitting inner spherical surface of the lower connector, achieving a hard-surface sealing effect. Since a sealing fit is formed between the tight-fitting outer spherical surface and the tight-fitting inner spherical surface, and a compression fit is formed between the abutting inner spherical surface and the abutting outer spherical surface, i.e., both are spherical adaptive structures, even when the axis of the upper pipe section and the axis of the lower pipe section are at a certain angle, a good hard-surface sealing contact can still be maintained, and the sealing surface opening phenomenon will not occur. The positive sealing groove and positive sealing element of the upper pipe section together form an elastic sealing surface. When the upper pipe section moves downward relative to the lower pipe section, the positive sealing element is further compressed to maintain the sealing state and block the steam leakage channel, thus preventing the generation of high-speed steam leakage. When the upper pipe section moves upward relative to the lower pipe section, the reverse sealing element is further compressed to maintain the sealing state and block the steam leakage channel, also preventing the generation of high-speed steam leakage. Therefore, the adaptive sealing docking structure can effectively cope with the opening of the main steam pipeline and allow for a large amount of forward and reverse displacement of the main steam pipeline. It can solve the steam leakage problem of high-parameter main steam pipelines, reduce the maintenance cost of high-parameter main steam pipelines by more than 30%, reduce the on-site installation requirements of high-parameter main steam pipelines, improve installation efficiency, and greatly reduce the requirements for flange connection bolts, reducing the number and specifications of bolts and nuts, thereby simplifying equipment manufacturing costs. Therefore, the adaptive sealing docking structure of the present invention, applicable to high-parameter main steam pipelines, can adapt to the misalignment deformation of the pipeline caused by installation or operation, as well as the changes in the vertical displacement of the sealing surface during operation. Attached Figure Description

[0022] Figure 1 Shown as a cross-sectional view of an adaptive sealing docking structure suitable for high-parameter main steam pipelines;

[0023] Figure 2Shown as an exploded view of an adaptive sealing docking structure suitable for high-parameter main steam pipelines.

[0024] Component designation explanation

[0025] 1. Upper Management Department

[0026] 2 Lower flange

[0027] 3 Upper flange

[0028] 4. Positive seal

[0029] 5. Reverse seal

[0030] 6. Pressure flange

[0031] 7. Tighten the bolts

[0032] 8 flange bolts

[0033] 9 Flange nuts

[0034] 10 Limiting Sleeve

[0035] 11 Lower Pipeline

[0036] 12 Annular protrusions

[0037] 13 Stress relief groove Detailed Implementation

[0038] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0039] It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings of this specification are merely for illustrative purposes to aid those skilled in the art and are not intended to limit the scope of the invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of the invention, should still fall within the scope of the technical content disclosed in this invention. Furthermore, the terms such as "upper," "lower," "left," "right," "middle," and "one" used in this specification are merely for clarity and are not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention's implementation.

[0040] like Figure 1 and Figure 2 As shown, the present invention provides an adaptive sealing connection structure suitable for high-parameter main steam pipelines, comprising:

[0041] The lower connector includes a lower pipe section 11 and a lower flange 2 formed on the outer peripheral wall of the lower pipe section 11. The pipe cavity of the lower pipe section 11 includes a large-diameter hole and a small-diameter hole that are axially connected. A closely fitting inner spherical surface is formed at the shoulder of the hole between the large-diameter hole and the small-diameter hole.

[0042] The upper connector includes an upper pipe section 1 and an upper flange 3 that abuts against the upper pipe section 1. The bottom end of the upper pipe section 1 forms a tight outer spherical surface. The bottom end of the upper pipe section 1 is inserted into the large diameter hole so that a sealing fit is formed between the tight outer spherical surface and the tight inner spherical surface. The upper pipe section 1 has a positive sealing groove and a reverse sealing groove on its outer peripheral wall inside the large diameter hole. The upper pipe section 1 has an annular protrusion 12 on its outer peripheral wall outside the large diameter hole. The annular protrusion 12 forms an abutting outer spherical surface on the side facing away from the lower connector. The upper flange 3 has a flange center hole that allows the upper pipe section 1 to pass through with a gap. The side of the upper flange 3 facing the lower connector forms an abutting inner spherical surface. A compression fit is formed between the abutting inner spherical surface and the abutting outer spherical surface.

[0043] A bidirectional sealing assembly includes a forward seal 4, a reverse seal 5, and a reverse pressure ring assembly. The forward seal 4 is embedded in the forward sealing groove and seals against the shoulder of the hole. The reverse seal 5 is disposed in the reverse sealing groove and seals against the wall of the large-diameter hole. The reverse pressure ring assembly is detachably disposed on the lower pipe 11 or the lower flange 2 and blocks the reverse seal 5 to confine the reverse seal 5 within the large-diameter hole.

[0044] The connecting assembly is detachably connected to the lower flange 2 and the upper flange 3 respectively, so that the lower flange 2 and the upper flange 3 are brought closer together.

[0045] The lower pipe section 11 and / or the upper pipe section 1 are used to connect to the high-parameter main steam pipeline.

[0046] In this invention, the lower pipe section 11 and the lower flange 2 can be integrally formed, while the upper pipe section 1 and the upper flange 3 are two independent components. When the sealing surface of the main steam pipeline opens due to installation welding deformation or operational thermal deformation, the adaptive sealing docking structure suitable for high-parameter main steam pipelines can adaptively rotate and maintain hard-surface sealing contact, preventing the formation of a steam leakage channel. When the main steam pipeline undergoes forward displacement, the forward sealing element forms a tight seal, blocking the steam leakage channel and preventing further damage to its own structure from high-speed steam leakage flow; when the main steam pipeline undergoes reverse displacement, the reverse sealing element 5 forms a tight seal, blocking the steam leakage channel and preventing further damage to its own structure from high-speed steam leakage flow.

[0047] Specifically: The tight outer spherical surface at the bottom of the upper pipe section 1 contacts the tight inner spherical surface of the lower connector (which can be a hard-face contact fit). As the upper flange 3 gradually approaches the lower flange 2 through the connecting assembly, the inner spherical surface of the large flange 3 adaptively transmits pressure to the outer spherical surface of the annular protrusion 12 of the upper pipe section 1, and finally through the pipe wall to the tight outer spherical surface at the bottom of the upper pipe section 1. This generates a certain sealing stress between the spherical surface at the bottom of the upper pipe section 1 and the tight inner spherical surface of the lower connector, achieving a hard-face sealing effect. Because a sealing fit is formed between the tight outer spherical surface and the tight inner spherical surface, and a compression fit is formed between the inner spherical surface and the outer spherical surface, both being spherical adaptive structures, even when the axis of the upper pipe section 1 and the axis of the lower pipe section 11 form a certain angle (not 180 degrees), a good hard-face sealing contact can still be maintained, and no sealing surface opening phenomenon will occur. The forward sealing groove of the upper pipe section 1 and the forward sealing element 4 together form an elastic sealing surface. When the upper pipe section 1 moves downward relative to the lower pipe section 11, the forward sealing element 4 is further compressed to maintain the sealing state and block the steam leakage channel, thus preventing the generation of high-speed steam leakage. When the upper pipe section 1 moves upward relative to the lower pipe section 11, the reverse sealing element 5 is further compressed to maintain the sealing state and block the steam leakage channel, also preventing the generation of high-speed steam leakage. Therefore, the adaptive sealing docking structure can effectively cope with the opening of the main steam pipeline and allow for a large forward and reverse displacement of the main steam pipeline. It can solve the steam leakage problem of high-parameter main steam pipelines, reduce the maintenance cost of high-parameter main steam pipelines by more than 30%, reduce the on-site installation requirements of high-parameter main steam pipelines, improve installation efficiency, and greatly reduce the requirements for flange connection bolts, reducing the number and specifications of bolts and nuts, thereby simplifying equipment manufacturing costs.

[0048] Therefore, the adaptive sealing docking structure of the present invention, applicable to high-parameter main steam pipelines, can adapt to the misalignment deformation of the pipeline caused by installation or operation, as well as the changes in the vertical displacement of the sealing surface during operation.

[0049] To better prevent the reverse seal 5 from being blocked, the reverse pressure ring assembly includes a ring-shaped clamping flange 6. The clamping flange 6 is sleeved on the upper pipe 1 and is provided on the lower pipe 11 or the lower flange 2 by clamping bolts 7. The inner periphery of the clamping flange 6 protrudes in a direction parallel to its own axis to form an annular locking protrusion. The annular locking protrusion extends into the large-diameter hole and blocks the reverse seal 5.

[0050] To facilitate the processing and formation of the forward or reverse sealing groove, the forward or reverse sealing groove has an annular stepped structure.

[0051] In order to adjust the tightness between the lower pipe section 11 and the upper pipe section 1, the connecting assembly includes a flange bolt 8 and a flange nut 9. The bottom end of the flange bolt 8 is threaded to the lower flange 2, the top end of the flange bolt 8 is passed through the upper flange 3, and the flange nut 9 is threaded to the top end of the flange bolt 8 and is pressed against the upper flange 3.

[0052] To avoid excessive compression between the lower pipe section 11 and the upper pipe section 1, and to prevent damage to the components, the connecting assembly also includes a limiting sleeve 10. The limiting sleeve 10 is fitted with the flange bolt 8 with a gap, and the limiting sleeve 10 is clamped between the lower flange 2 and the upper flange 3.

[0053] Because reverse sealing is more difficult than forward sealing, and in order to control overall costs, the forward sealing element 4 is a single sealing ring, while the reverse sealing element 5 is composed of multiple sealing rings stacked one on top of the other.

[0054] In order to release stress in the lower connector when the pipe is misaligned and deformed, a stress relief groove 13 is provided on the wall of the large-diameter hole, and the stress relief groove 13 is located between the positive sealing groove and the reverse sealing groove.

[0055] To facilitate monitoring of steam leakage, the lower connector is equipped with a pressure monitoring hole, which is connected to the stress relief tank 13. When a leak occurs, steam will flow into the stress relief tank 13 and then into the pressure monitoring hole.

[0056] Furthermore, a pressure sensor is installed inside the pressure monitoring port. The addition of the pressure sensor allows for real-time monitoring of steam leakage.

[0057] To prevent steam from leaking into the plant, the lower connector is equipped with a steam guide channel, which connects to the stress relief tank 13 and to a steam exhaust area located outside the plant. In the event of a leak, steam flows sequentially through the stress relief tank 13, the steam guide channel, and the steam exhaust area.

[0058] In summary, this invention is applicable to the adaptive sealing and docking structure of high-parameter main steam pipelines, capable of adapting to pipeline misalignment deformation caused by installation or operation, as well as vertical displacement changes on the sealing surface during operation. Therefore, this invention effectively overcomes the various shortcomings of existing technologies and has high industrial application value.

[0059] The embodiments described are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the embodiments without departing from the spirit and scope of the invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. An adaptive sealing connection structure suitable for high-parameter main steam pipelines, characterized in that, include: The lower connector includes a lower pipe section (11) and a lower flange (2) formed on the outer peripheral wall of the lower pipe section (11). The pipe cavity of the lower pipe section (11) includes a large-diameter hole and a small-diameter hole that are axially connected. A closely spaced inner spherical surface is formed at the shoulder of the hole between the large-diameter hole and the small-diameter hole. The upper connector includes an upper pipe section (1) and an upper flange (3) that abuts against the upper pipe section (1). The bottom end of the upper pipe section (1) forms a tight outer spherical surface. The bottom end of the upper pipe section (1) is inserted into the large diameter hole so that a sealing fit relationship is formed between the tight outer spherical surface and the tight inner spherical surface. The upper pipe section (1) has a positive sealing groove and a reverse sealing groove on its outer peripheral wall inside the large diameter hole. The upper pipe section (1) has an annular protrusion (12) on its outer peripheral wall outside the large diameter hole. The annular protrusion (12) forms an abutting outer spherical surface on the side facing the lower connector. The upper flange (3) has a flange center hole that allows the upper pipe section (1) to pass through the gap. The upper flange (3) forms an abutting inner spherical surface on the side facing the lower connector. A compression fit relationship is formed between the abutting inner spherical surface and the abutting outer spherical surface. A bidirectional sealing assembly includes a forward seal (4), a reverse seal (5), and a reverse pressure ring assembly. The forward seal (4) is embedded in the forward sealing groove and seals against the shoulder of the bore. The reverse seal (5) is located in the reverse sealing groove and seals against the wall of the large-diameter bore. The reverse pressure ring assembly is detachably mounted on the lower pipe section (11) or the lower flange (2) and blocks the reverse seal (5) to confine it within the large-diameter bore. The positive sealing groove of the upper tube (1) and the positive sealing element (4) together form an elastic sealing surface. When the upper tube (1) moves downward relative to the lower tube (11), the positive sealing element (4) is further pressed. When the upper tube (1) moves upward relative to the lower tube (11), the reverse sealing element (5) is further pressed. The large-diameter hole is provided with a stress relief groove (13) on the hole wall. The stress relief groove (13) is located between the positive sealing groove and the reverse sealing groove. The connecting assembly is detachably connected to the lower flange (2) and the upper flange (3) respectively, so that the lower flange (2) and the upper flange (3) are brought close together and connected; The lower pipe section (11) and / or the upper pipe section (1) are used to connect to the high-parameter main steam pipeline.

2. The adaptive sealing connection structure for high-parameter main steam pipelines according to claim 1, characterized in that: The reverse pressure ring assembly includes a ring-shaped pressure flange (6), which is fitted onto the upper pipe (1) and is mounted on the lower pipe (11) or lower flange (2) by a pressure bolt (7). The inner periphery of the pressure flange (6) protrudes along its own axis to form an annular locking protrusion, which extends into the large-diameter hole and blocks the reverse seal (5).

3. The adaptive sealing connection structure for high-parameter main steam pipelines according to claim 1, characterized in that: The forward or reverse sealing groove has an annular stepped structure.

4. The adaptive sealing connection structure for high-parameter main steam pipelines according to claim 1, characterized in that: The connecting assembly includes a flange bolt (8) and a flange nut (9). The bottom end of the flange bolt (8) is threaded to the lower flange (2), and the top end of the flange bolt (8) passes through the upper flange (3). The flange nut (9) is threaded to the top end of the flange bolt (8) and is pressed against the upper flange (3).

5. The adaptive sealing connection structure for high-parameter main steam pipelines according to claim 4, characterized in that: The connecting assembly also includes a limiting sleeve (10), which is fitted onto the flange bolt (8) with a gap, and is clamped between the lower flange (2) and the upper flange (3).

6. The adaptive sealing connection structure for high-parameter main steam pipelines according to claim 1, characterized in that: The forward seal (4) is a single sealing ring, and the reverse seal (5) is composed of multiple sealing rings stacked one on top of the other.

7. The adaptive sealing connection structure for high-parameter main steam pipelines according to claim 1, characterized in that: The lower connector is provided with a pressure monitoring hole, which is connected to the stress relief groove (13).

8. The adaptive sealing connection structure for high-parameter main steam pipelines according to claim 7, characterized in that: A pressure sensor is installed inside the pressure monitoring port.

9. The adaptive sealing connection structure for high-parameter main steam pipelines according to claim 1, characterized in that: The lower connector is provided with a steam guide channel, which is connected to the stress relief groove (13) and to a steam exhaust area located outside the plant.

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