A pipe connection structure through a multi-layer casing

Abstract

The application provides a pipeline connecting structure penetrating through a multilayer casing, and belongs to the technical field of aeroengines. The pipeline connecting structure comprises an outer casing, an inner casing, a sealing casing, and an intermediate casing between the outer casing and the inner casing. The intermediate casing comprises an outer ring, a support plate, and an inner ring. An outer channel is formed between the outer ring and the outer casing. A cooling gas passage is formed between the inner casing and the sealing casing. A main flow passage is formed between the outer ring and the inner ring. A heat insulation cavity is formed between the inner ring and the inner casing. The pipeline welding assembly is mainly composed of a pipe joint, a sleeve, a pipeline, and a sleeve plug. The pipeline welding assembly penetrates through the outer casing, the intermediate casing, and the inner casing and is installed on the sealing casing. The pipeline welding assembly is fixedly connected with the intermediate casing. The pipeline welding assembly is floatingly sealed with the outer casing and the inner casing. The pipeline welding assembly is inserted with the sealing casing and is sealed by using a sealing structure based on expanded graphite.

Description

Technical Field

[0001] This application belongs to the field of aero-engines, and specifically relates to a pipe connection structure that runs through multiple layers of the casing. Background Technology

[0002] Piping connections traversing multiple casings are a common feature in aero-engines. As the main flow channel temperature of aero-engines increases, the temperature and deformation differences between casings also increase, posing significant challenges to the design of piping connections through these multiple casings. Higher ambient temperatures can heat the media inside the piping (such as lubricating oil and sealing gas), leading to problems like lubricating oil coking and excessively high sealing gas temperatures. Furthermore, higher ambient temperatures can affect the reliable sealing between the piping and the sealing cavity.

[0003] In existing technologies, the installation of multi-layer casing pipelines is often achieved by fixing the pipeline to a single-layer casing and leaving a large gap between it and other casings. This method can avoid the problem of stress caused by friction at the contact point between the pipeline and the multi-layer casing due to the incoordination of the multi-layer casing. However, this method will cause sealing problems between the multi-layer casings at the gap, resulting in media leakage.

[0004] In addition, regarding issues such as lubricating oil and sealing gas insulation in pipelines, since pipelines are usually single-layered pipes or have simple sleeve structures added for insulation, this method cannot meet the insulation and cooling requirements of pipelines when the main channel temperature is high.

[0005] Finally, regarding the sealing problem between pipelines and sealing cavities or casings, existing technologies often use rubber ring seals between pipelines and sealing casings. During assembly, inserting the pipeline into the sealing casing may damage the surface integrity of the rubber ring, thus affecting the reliability of the lubricating oil seal. It also cannot effectively seal the pipeline when it moves significantly under different operating conditions, resulting in leakage. Summary of the Invention

[0006] The purpose of this application is to provide a through-hole pipe connection structure to solve or mitigate at least one of the problems in the prior art.

[0007] The technical solution of this application is: a pipe connection structure penetrating multiple layers of the casing, comprising:

[0008] Outer casing;

[0009] Inner casing;

[0010] Sealed housing;

[0011] An intermediate casing is located between the outer casing and the inner casing. The intermediate casing includes an outer ring, a support plate, and an inner ring. The outer ring and the outer casing form an outer bypass duct. The inner casing and the sealed casing form a cooling gas passage. The outer ring and the inner ring form a main flow gas passage. The inner ring and the inner casing form a heat insulation cavity.

[0012] The pipeline welding assembly mainly consists of pipe fittings, sleeves, pipelines, and sleeve plugs. The pipeline welding assembly passes through the outer casing, intermediate casing, and inner casing and is installed on the sealing casing. The pipeline welding assembly is fixedly connected to the intermediate casing, floatingly sealed to the outer casing and inner casing, and plugged into the sealing casing. It adopts a sealing structure based on expanded graphite for sealing.

[0013] In a preferred embodiment of this application, the sleeve is disposed on the outside of the pipeline, and both ends of the sleeve and the pipeline are respectively connected to the pipe joint and the sleeve plug, thereby forming a pipeline welding assembly with a sandwich cavity.

[0014] In a preferred embodiment of this application, the sleeve is provided with an air inlet and an air outlet. The air inlet is located inside the outer duct, and the air outlet is located inside the heat insulation cavity. The outer duct air enters from the air inlet, flows along the interlayer cavity, and flows out from the air outlet.

[0015] In a preferred embodiment of this application, the sleeve and pipeline are fixed to the pipe joint and sleeve plug by welding.

[0016] In a preferred embodiment of this application, the pipeline welding assembly further includes a mounting flange, which is fixed to the sleeve, and the pipeline welding assembly is fixedly connected to the intermediate casing through the mounting flange.

[0017] In a preferred embodiment of this application, the pipeline connection structure further includes a first sealing ring, which is a split overlapping structure. The pipe joint is a double-flange structure, and the outer casing is provided with a sleeve-type mounting seat. The upper and lower end faces of the first sealing ring are assembled between the double-flange of the pipe joint, and the outer circular surface of the first sealing ring contacts the inner surface of the sleeve-type mounting seat of the outer casing. The contact end faces of the first sealing ring, the outer casing, and the pipe joint are all clearance fits, thereby achieving floating sealing of the pipeline welding assembly and the outer casing in the axial, circumferential, and radial directions.

[0018] In a preferred embodiment of this application, the upper and lower end faces and the outer circular surface of the first sealing ring are provided with a wear-resistant coating.

[0019] In a preferred embodiment of this application, the pipeline connection structure further includes a floating ring and a cover plate. The cover plate is fixed on the inner casing to form an annular gap. The floating ring is installed in the annular gap and contacts the surface of the sleeve plug. The upper and lower surfaces of the floating ring are in clearance fit with the cover plate, and the floating ring is in clearance fit with the sleeve plug, thereby achieving floating sealing of the pipeline welding assembly and the inner casing in the axial, circumferential, and radial directions.

[0020] In a preferred embodiment of this application, the pipeline connection structure further includes a clamping nut, a gasket, and a second sealing ring. The clamping nut, gasket, and second sealing ring are fitted onto the outside of the pipeline. The pipeline is assembled onto the sealing housing via the clamping nut. The material of the second sealing ring is expanded graphite. The second sealing ring and the pipeline are in a clearance fit. Under the clamping action of the clamping nut, the second sealing ring will undergo compression deformation, thereby achieving a tight fit with the pipeline and realizing a seal between the pipeline and the sealing housing.

[0021] In a preferred embodiment of this application, sealing of different media is achieved by adjusting the number of second sealing rings.

[0022] The pipeline connection structure provided in this application, which penetrates multiple casings, mounts the pipelines on a high-temperature intermediate casing. Different types of floating sealing structures are designed between the pipelines and other casings according to the working environment and requirements. This solves the problems of pipeline wear and leakage between different media cavities caused by inconsistent thermal deformation between casings. Furthermore, this pipeline connection structure provides a double-layer pipeline structure with a cooling flow path designed between the pipeline and the sleeve, achieving efficient thermal insulation and cooling of the pipeline. The pipeline connection structure of this application also provides an expanded graphite sealing structure that can be used to seal high-pressure, high-temperature gas and oil media, achieving a highly reliable sealing effect. Attached Figure Description

[0023] To more clearly illustrate the technical solutions provided in this application, the accompanying drawings will be briefly described below. Obviously, the drawings described below are merely some embodiments of this application.

[0024] Figure 1 This is a general schematic diagram of the piping connection structure that runs through the multi-layer casing of this application.

[0025] Figure 2 This is a schematic diagram of the first sealing ring in this application.

[0026] Figure 3 This is a schematic diagram of the pipe welding assembly and the floating seal of the outer casing in this application.

[0027] Figure 4 This is a schematic diagram of the pipe welding assembly and the floating seal of the inner casing in this application.

[0028] Figure 5 This is a schematic diagram showing the connection between the pipe welding assembly and the sealing casing in this application.

[0029] Figure 6 This is a schematic diagram of the flow path of the interlayer cavity in the pipeline welding assembly of this application.

[0030] Figure label:

[0031] 1-Pipe fitting;

[0032] 2-First sealing ring;

[0033] 3-Outer casing;

[0034] 4-Casing;

[0035] 41 - Air intake port;

[0036] 42 - Vent hole;

[0037] 5-Installation flange;

[0038] 6- Piping;

[0039] 7-Intermediate casing;

[0040] 71-Outer Ring;

[0041] 72-Support plate;

[0042] 73-Inner Ring;

[0043] 8-Casing plug;

[0044] 9-Floating ring;

[0045] 10-Cover plate;

[0046] 11-Inner casing;

[0047] 12-Compression nut;

[0048] 13-Gasket;

[0049] 14 - Second sealing ring;

[0050] 15-Sealed casing. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings.

[0052] In order to solve the problems of insufficient wear and sealing between the pipeline and the multi-layer casing in the prior art, insufficient heat insulation and cooling effect of the pipeline due to high main channel temperature, or failure to achieve reliable sealing between the pipeline and the sealing cavity when the pipeline working state is greatly affected by damage to the seals during pipeline assembly, this application provides a pipeline connection structure that runs through the multi-layer casing.

[0053] This application uses the example of passing through four layers of casing for illustration.

[0054] like Figure 1 As shown, the pipeline connection structure through the multi-layer casing provided in this application mainly includes: pipe joint 1, first sealing ring 2, outer casing 3, sleeve 4, mounting flange 5, pipeline 6, intermediate casing 7, sleeve plug 8, floating ring 9, cover plate 10, inner casing 11, clamping nut 12, gasket 13, second sealing ring 14, and sealing casing 15.

[0055] The two ends of the sleeve 4 and the pipe 6 are respectively welded to the pipe joint 1 and the sleeve plug 8 to form a double-layer pipe welding assembly. The mounting flange 5 is welded to the pipe welding assembly, and the sleeve 4 is positioned and connected by the sleeve plug 8.

[0056] The intermediate casing 7 mainly consists of an outer ring 71, a support plate 72, and an inner ring 73. The outer casing 3 and the outer ring 71 of the intermediate casing 7 form an outer bypass air passage with a lower ambient temperature. The outer ring 71 and the inner ring 73 of the intermediate casing 7 form a main flow air passage with a higher ambient temperature. The inner casing 11 and the sealed casing 15 form a cooling air passage with a moderate ambient temperature (between the temperatures of the outer bypass air passage and the main flow air passage). The inner ring 73 of the intermediate casing 7 and the inner casing 11 form a heat insulation cavity to reduce the heating effect of the high temperature of the main flow on the cooling air.

[0057] The pipeline welding assembly is fixedly connected to the intermediate casing 7, while a floating seal is used between the pipeline welding assembly and the outer casing 3 and inner casing 11. The pipeline welding assembly is plugged into the sealing casing 15, employing a sealing structure based on expanded graphite. This structure prevents friction between the casings and the pipeline welding assembly when the outer casing 3, intermediate casing 7, and inner casing 11 experience inconsistent thermal deformation. It also ensures a good seal between the casings, preventing media leakage. The expanded graphite-based sealing structure prevents damage to the seals during pipeline assembly and ensures a reliable seal between the pipeline and the sealing casing 15 even when the pipeline experiences radial movement due to changes in operating conditions.

[0058] In this application, since changes in the main duct gas directly affect engine performance, a strict seal between the main duct gas and the bypass gas is required. Therefore, the pipe welding assembly in this application is fixedly connected to the intermediate casing 7 via mounting flange 5 (e.g., bolt connection), ensuring no leakage between the main duct gas and the bypass gas. The outer side of the outer casing 3 is the external atmospheric environment of the engine; a slight leakage of the bypass gas has almost no impact on engine performance; a slight leakage of the cooling gas also has almost no impact on the cooling of the lubricating oil chamber. Therefore, the pipe welding assembly, the outer casing 3, and the inner casing 11 all employ floating seals.

[0059] In this application, in the aero-engine environment, due to the influence of the main flow ambient temperature, the temperature of the intermediate casing 7 is usually much higher than that of the outer casing 3, and its circumferential, axial, and radial deformations differ greatly from those of the outer casing. The floating seal of the outer casing 3 adopts an external sealing ring type floating seal structure. Figure 2 As shown, the first sealing ring 2 is designed as a split overlapping structure, and wear-resistant coatings can be applied to the upper and lower end faces and the outer circular surface as needed. Figure 3 As shown, the pipe fitting 1 has a double-flange structure, and the outer casing 3 is provided with a sleeve-type mounting seat. The upper and lower end faces of the first sealing ring 2 are assembled between the double-flange of the pipe fitting 1, and the outer circular surface of the first sealing ring 2 contacts the inner surface of the sleeve-type mounting seat of the outer casing 3. The contact end face fit dimensions of the first sealing ring 2, the outer casing 3, and the pipe fitting 1 are all small clearance fits, thereby realizing the floating seal of the pipeline welding assembly and the outer casing 3 in the axial, circumferential, and radial directions.

[0060] like Figure 4 As shown, due to space constraints in the design of the inner casing 11, the floating sealing structure in this application adopts a cover-plate type internal floating sealing structure—the cover plate 10 is fixed to the inner casing 11 by screws or welding, forming an annular gap between them. The floating ring 9 is installed within this annular gap and contacts the surface of the sleeve plug 8. The upper and lower surfaces of the floating ring 9 have small clearances with the cover plate 10, and the floating ring 9 has small clearances with the sleeve plug 8, thereby achieving floating sealing of the pipeline welding assembly and the inner casing 11 in the axial, circumferential, and radial directions. In a preferred embodiment of this application, the floating ring 9 has an L-shaped cross-section, with its extended side pointing towards the outer casing direction on the side contacting the sleeve plug 8.

[0061] like Figure 5The diagram shows a high-reliability sealing structure between pipe 6 and sealing housing 15. Pipe 6 is fitted with a clamping nut 12, which, after being assembled into the sealing housing 15, is tightened to secure it. Inside the sealing housing 15 below the clamping nut 12, a gasket 13 and a second sealing ring 14 are sequentially arranged. The second sealing ring 14 is made of expanded graphite, and its fit with pipe 6 is designed with a clearance fit (clearance H1 > 0), thus preventing damage to the second sealing ring 14 during pipe 6 assembly. Under the action of the clamping nut 12, the second sealing ring 14 undergoes compression deformation, resulting in a tight fit with pipe 6 (clearance H1 = 0), achieving a seal between pipe 6 and sealing housing 15.

[0062] When the engine operating conditions change significantly, the pipeline 6 and the sealing casing 15 experience significant radial movement. Since the material of the second sealing ring 14 is expanded graphite, which has lubricating properties, the damage to the second sealing ring 14 is minimal when the pipeline 6 moves. Furthermore, as the temperature rises, the graphite expands in volume, enabling reliable sealing of various media.

[0063] By adjusting the number of the second sealing rings 14, sealing can be achieved for different media. For example, when sealing lubricating oil, the number of the second sealing rings 14 can be appropriately increased, while when sealing gas, the number of the second sealing rings 14 can be reduced.

[0064] like Figure 6 The diagram shows a schematic of the high-efficiency heat insulation and cooling structure of the pipeline welding assembly. In this structure, a sleeve 4 is installed on the outside of the pipeline 6, and a sandwich cavity for gas flow is formed between the two. The sleeve 4 is provided with an air inlet 41 and an air outlet 42. The air inlet 41 is located in the outer bypass gas channel with lower temperature and higher pressure. The outer bypass gas enters the sandwich cavity between the sleeve 4 and the pipeline 6 from the air inlet 41 and flows out from the air outlet 42, which meets the high-efficiency cooling and heat insulation requirements of the pipeline 6.

[0065] The pipeline connection structure provided in this application, which penetrates multiple casings, mounts the pipelines on a high-temperature intermediate casing. Different types of floating sealing structures are designed between the pipelines and other casings according to the working environment and requirements. This solves the problems of pipeline wear and leakage between different media cavities caused by inconsistent thermal deformation between casings. Furthermore, this pipeline connection structure provides a double-layer pipeline structure with a cooling flow path designed between the pipeline and the sleeve, achieving efficient thermal insulation and cooling of the pipeline. The pipeline connection structure of this application also provides an expanded graphite sealing structure that can be used to seal high-pressure, high-temperature gas and oil media, achieving a highly reliable sealing effect.

[0066] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A pipe connection structure penetrating a multi-layer casing, characterized in that, include: Outer casing (3); Inner casing (11); Sealed housing (15); An intermediate casing (7) is located between the outer casing (3) and the inner casing (11). The intermediate casing (7) includes an outer ring (71), a support plate (72), and an inner ring (73). The outer ring (71) and the outer casing (3) form an outer bypass duct. The inner casing (11) and the sealed casing (15) form a cooling air passage. The outer ring (71) and the inner ring (73) form a main flow air passage. The inner ring (73) and the inner casing (11) form a heat insulation cavity. The pipeline welding assembly is mainly composed of a pipe fitting (1), a sleeve (4), a pipeline (6), and a sleeve plug (8). The pipeline welding assembly passes through the outer casing (3), the intermediate casing (7), and the inner casing (11) and is installed on the sealing casing (15). The pipeline welding assembly is fixedly connected to the intermediate casing (7), floatingly sealed to the outer casing (3) and the inner casing (11), and plugged into the sealing casing (15). It is sealed using a sealing structure based on expanded graphite.

2. The pipe connection structure penetrating multiple layers of the casing as described in claim 1, characterized in that, The sleeve (4) is disposed on the outside of the pipeline (6), and the two ends of the sleeve (4) and the pipeline (6) are respectively connected to the pipe joint (1) and the sleeve plug (8), thereby forming a pipeline welding assembly with a sandwich cavity.

3. The through-multi-layer casing piping connection structure as described in claim 2, characterized in that, The sleeve (4) is provided with an air inlet (41) and an air outlet (42). The air inlet (41) is located inside the outer duct, and the air outlet (42) is located inside the heat insulation cavity. The outer duct gas enters from the air inlet (41), flows along the interlayer cavity, and flows out from the air outlet (42).

4. The through-multi-layer casing piping connection structure as described in claim 2 or 3, characterized in that, The sleeve (4) and pipe (6) are fixed to the pipe joint (1) and sleeve plug (8) by welding.

5. The through-multi-layer casing piping connection structure as described in claim 4, characterized in that, The pipeline welding assembly also includes a mounting flange (5), which is fixed to the sleeve (4), and the pipeline welding assembly is fixedly connected to the intermediate casing (7) through the mounting flange (5).

6. The through-multi-layer casing piping connection structure as described in claim 1, characterized in that, The pipeline connection structure also includes a first sealing ring (2), which is a split overlapping structure. The pipe joint (1) is a double-flange structure. The outer casing (3) is provided with a sleeve-type mounting seat. The upper and lower end faces of the first sealing ring (2) are assembled between the double-flange of the pipe joint (1), and the outer circular surface of the first sealing ring (2) contacts the inner surface of the sleeve-type mounting seat of the outer casing (3). The contact end face fit dimensions of the first sealing ring (2) with the outer casing (3) and the pipe joint (1) are all clearance fits, thereby realizing the floating sealing of the pipeline welding assembly with the outer casing in the axial, circumferential and radial directions.

7. The through-multi-layer casing piping connection structure as described in claim 6, characterized in that, The upper and lower end faces and the outer circular surface of the first sealing ring (2) are provided with a wear-resistant coating.

8. The through-multi-layer casing piping connection structure as described in claim 1, characterized in that, The pipeline connection structure also includes a floating ring (9) and a cover plate (10). The cover plate (10) is fixed on the inner casing (11) to form an annular gap. The floating ring (9) is installed in the annular gap and contacts the surface of the sleeve plug (8). The upper and lower surfaces of the floating ring (9) are in clearance fit with the cover plate (10) and with the sleeve plug (8), thereby achieving floating sealing of the pipeline welding assembly and the inner casing in the axial, circumferential and radial directions.

9. The pipe connection structure penetrating multiple layers of the casing as described in claim 1, characterized in that, The pipeline connection structure also includes a clamping nut (12), a gasket (13), and a second sealing ring (14). The pipeline (6) is fitted with a clamping nut (12), a gasket (13), and a second sealing ring (14). The pipeline (6) is assembled onto the sealing housing (15) through the clamping nut (12). The material of the second sealing ring (14) is expanded graphite. The second sealing ring (14) and the pipeline (6) are in clearance fit. The second sealing ring (14) will be compressed and deformed under the clamping action of the clamping nut (12), so that it is in a tight fit with the pipeline (6), thereby achieving a seal between the pipeline (6) and the sealing housing (15).

10. The through-multi-layer casing piping connection structure as described in claim 9, characterized in that, By adjusting the number of the second sealing rings (14), sealing can be achieved for different media.

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