A manhole flange sealing structure for rocket cryogenic tanks

Abstract

This application discloses a manhole flange sealing structure for a rocket cryogenic storage tank, comprising: a manhole flange cover, a manhole flange, a combined sealing ring with adaptive sealing surface performance, and bolts; the sealing surface of the manhole flange cover is provided with a tenon structure; the sealing surface of the manhole flange is provided with a stepped groove structure; the combined sealing ring is disposed within the stepped groove structure; during connection, the sealing surface of the manhole flange cover contacts the sealing surface of the manhole flange, the tenon structure is located within the stepped groove structure and contacts the combined sealing ring, and the manhole flange cover and manhole flange are fastened together by bolts. This application adopts a tenon-groove flange sealing structure, which can ensure a tight fit between the sealing ring and the sealing surface, while increasing the flow resistance of medium leakage at the sealing surface, thus possessing reliable sealing performance.

Description

Technical Field

[0001] This application relates to the field of aerospace technology, and in particular to a manhole flange sealing structure for a rocket cryogenic tank. Background Technology

[0002] The manhole flange of a rocket cryogenic storage tank is a critical component for ensuring no leakage of the medium inside the tank, and it must also maintain good sealing performance even after repeated disassembly and installation. The requirements for rocket cryogenic storage tank manhole flanges generally include: reliable connection, capable of withstanding the maximum working load inside the tank; reliable sealing, meeting leakage rate requirements; low fluid resistance; and simple structure and small size, facilitating repeated disassembly, maintenance, and replacement.

[0003] Common sealing structures for manhole flanges in rocket cryogenic storage tanks include three main types: flat flange sealing, raised face flange sealing, and tongue and groove flange sealing. Flat flange sealing is simple, easy to manufacture, install, and replace. However, due to the large contact area between the sealing surface and the gasket, improper pre-tightening can cause the gasket to be squeezed out of the sealing surface, and it is difficult to tighten, resulting in poor sealing performance. Raised face flange sealing is also a wide sealing surface type, easy to align during installation, and effectively prevents the gasket from being squeezed out of the sealing surface. While its sealing performance is better than flat flange sealing, its sealing reliability is insufficient. Tongue and groove flange sealing consists of a tongue and a groove, resulting in a narrow sealing surface. Due to the obstruction of the groove, the gasket will not be squeezed out of the pressing surface and is less susceptible to erosion and corrosion from the medium. It is easy to align during installation, the gasket is evenly stressed, and the seal is reliable, but gasket replacement is difficult. Furthermore, in cryogenic environments such as liquid oxygen (-183℃) or liquid hydrogen (-253℃), conventional flange sealing structures are prone to hardening and brittleness of the sealing materials. Moreover, cold contraction and deformation can cause preload relaxation, leading to low-temperature creep and ultimately resulting in excessive leakage. Achieving good cryogenic sealing performance requires careful design of the sealing structure and selection of appropriate sealing materials. Summary of the Invention

[0004] The purpose of this application is to provide a manhole flange sealing structure for rocket cryogenic storage tanks. The structure adopts a tongue and groove flange sealing structure, which can ensure that the sealing ring and the sealing surface are tightly fitted, while increasing the flow resistance of medium leakage at the sealing surface and having reliable sealing performance.

[0005] To achieve the above objectives, this application provides a manhole flange sealing structure for a rocket cryogenic storage tank, comprising: a manhole flange cover, a manhole flange, a combined sealing ring with adaptive sealing surface performance, and bolts; a tenon structure is provided on the sealing surface of the manhole flange cover; a stepped groove structure is provided on the sealing surface of the manhole flange; the combined sealing ring is disposed within the stepped groove structure; during connection, the sealing surface of the manhole flange cover contacts the sealing surface of the manhole flange, the tenon structure is located within the stepped groove structure and contacts the combined sealing ring, and the manhole flange cover and the manhole flange are fastened together by bolts.

[0006] As described above, the manhole flange cover includes at least: a convex head and an upper flange ring; the upper flange ring is disposed around the convex head; the upper flange ring is provided with multiple bolt through holes; the bottom of the upper flange ring is used as the sealing surface, and at least one tenon structure is provided on the sealing surface.

[0007] As shown above, the tenon structure is located on the sealing surface between the bolt through hole and the convex end cap.

[0008] As shown above, the tenon structure is a protrusion with a rectangular cross-section.

[0009] As described above, the manhole flange includes at least: a lower flange ring and a tapered ring for connecting to the housing; the tapered ring is disposed around the lower flange ring; the lower flange ring is provided with multiple connection holes; the top of the lower flange ring is used as the sealing surface, and at least one stepped groove structure is formed on the sealing surface.

[0010] As shown above, the stepped groove structure is located on the sealing surface of the connecting hole on the side away from the conical ring.

[0011] As described above, the stepped groove structure includes at least an upper groove and a lower groove. The cross-sectional width of the lower groove is smaller than that of the upper groove. The side of the upper groove near the connecting hole is aligned with the side of the lower groove near the connecting hole. The lower side of the upper groove is connected to the upper side of the lower groove.

[0012] As described above, the combined sealing ring includes at least: an open sealing outer ring and an O-ring inner ring; the open sealing outer ring includes: an upper sealing plate, a side sealing plate, and a lower sealing plate, one end of the upper sealing plate is connected to one end of the side sealing plate, and one end of the lower sealing plate is connected to the other end of the side sealing plate, forming an open structure after connection; a sealing protrusion is provided on the side of the side sealing plate away from the upper sealing plate, and the sealing protrusion is located at the end of the side sealing plate close to the upper sealing plate; the O-ring inner ring is set in the open structure; in use, the parts of the lower sealing plate and the side sealing plate without the sealing protrusion and a part of the O-ring inner ring are all located in the lower groove, and the parts of the upper sealing plate and the side sealing plate with the sealing protrusion and a part of the O-ring inner ring are all located in the upper groove; after the bolts pass through the bolt through holes and the connecting holes to fasten the manhole flange cover and the manhole flange, the tenon structure is located in the upper groove and contacts the upper side of the upper sealing plate, the side of the sealing protrusion away from the side sealing plate contacts the side of the upper groove away from the connecting hole, and the O-ring inner ring adapts to deformation due to compression.

[0013] As shown above, the outer ring of the opening seal is made of polytetrafluoroethylene material with low-temperature resistance.

[0014] As shown above, the inner O-ring is an O-ring metal spring skeleton rubber ring.

[0015] The beneficial effects achieved by this application are as follows:

[0016] (1) The manhole flange sealing structure for rocket cryogenic storage tanks in this application adopts a stepped tenon and groove sealing structure. The boss tenon and the trapezoidal groove can ensure that the flange is easy to align during installation and can effectively prevent the sealing ring from being squeezed out of the sealing surface.

[0017] (2) The manhole flange sealing structure for rocket cryogenic storage tanks in this application eliminates the flange neck structure commonly used in general flanges, and designs the thickness of the upper / lower flange rings according to the load-bearing capacity. The end faces of the upper / lower flange rings are fitted together. This structure can minimize the weight of the manhole flange, while the fitted assembly increases the overall rigidity of the manhole flange, so that the coefficient of the flange structure is minimized.

[0018] (3) The combined sealing ring of this application does not harden or become brittle in a cryogenic working environment and still has excellent resilience. At the same time, under the extrusion and rebound force of the inner sealing ring, it can increase the contact area between the sealing ring and the flange sealing surface and ensure tight contact. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings.

[0020] Figure 1 A partial schematic diagram of one embodiment of a manhole flange sealing structure used in a rocket cryogenic tank;

[0021] Figure 2 for Figure 1 A magnified view of part A in the image;

[0022] Figure 3 A schematic diagram of one embodiment of a manhole flange cover;

[0023] Figure 4 A schematic diagram of one embodiment of a manhole flange;

[0024] Figure 5 This is a schematic diagram of one embodiment of a combined sealing ring. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] like Figure 1 and 2 As shown, this application provides a manhole flange sealing structure for a rocket cryogenic storage tank, including: a manhole flange cover 1, a manhole flange 2, a combined sealing ring 3 with adaptive sealing surface performance, and bolts; a tenon structure 11 is provided on the sealing surface of the manhole flange cover 1; a stepped groove structure 21 is provided on the sealing surface of the manhole flange 2; the combined sealing ring 3 is disposed within the stepped groove structure 21; during connection, the sealing surface of the manhole flange cover 1 contacts the sealing surface of the manhole flange 2, the tenon structure 11 is located within the stepped groove structure 21 and contacts the combined sealing ring 3, and the manhole flange cover 1 and the manhole flange 2 are fastened together by bolts.

[0027] Specifically, the manhole flange sealing structure for rocket cryogenic tanks in this application adopts a tongue and groove flange sealing structure.

[0028] Furthermore, such as Figure 3As shown, the manhole flange cover 1 includes at least: a convex head 12 and an upper flange ring 13, the upper flange ring 13 being disposed around the convex head 12; the upper flange ring 13 being provided with a plurality of bolt through holes 131; the bottom of the upper flange ring 13 being used as a sealing surface, and at least one tenon structure 11 being provided on the sealing surface.

[0029] Specifically, the manhole flange cover 1 can be a separate structure or an integral structure; this application prefers an integral structure, with the manhole flange cover 1 being machined as a whole. Considering weight reduction for the manhole flange, the thickness of the upper flange ring 13 is designed based on the maximum load the manhole flange can withstand. The specific number of tenon structures 11 depends on the actual situation. This application preferably uses one, and the tenon structure 11 is a ring structure.

[0030] When there are multiple tenon structures 11, each tenon structure 11 is a non-circular structure.

[0031] Furthermore, the tenon structure 11 is located on the sealing surface between the bolt through hole 131 and the convex end cap 12.

[0032] Furthermore, the tenon structure 11 is a protrusion with a rectangular cross-section, but it is not limited to a rectangular protrusion. In this application, a rectangular protrusion is preferred.

[0033] Furthermore, such as Figure 4 As shown, the manhole flange 2 includes at least: a lower flange ring 22 and a tapered ring 23 for connecting to the housing; the tapered ring 23 is disposed around the lower flange ring 22; the lower flange ring 22 is provided with a plurality of connection holes 221; the top of the lower flange ring 22 is used as a sealing surface, and at least one stepped groove structure 21 is formed on the sealing surface.

[0034] Specifically, the manhole flange 2 can be a separate structure or an integral structure; this application prefers an integral structure, with the manhole flange 2 being machined as a whole. Considering weight reduction for the manhole flange, the thickness of the lower flange ring 22 is designed based on the maximum load the manhole flange can withstand. The specific number of stepped groove structures 21 depends on the actual situation. This application preferably uses one, and the stepped groove structure 21 is a ring structure.

[0035] When there are multiple stepped groove structures 21, each stepped groove structure 21 is a non-ring structure.

[0036] Furthermore, the stepped groove structure 21 is located on the sealing surface of the connecting hole 221 on the side away from the conical ring 23.

[0037] Furthermore, the stepped groove structure 21 includes at least an upper groove 211 and a lower groove 212. The cross-sectional width of the lower groove 212 is smaller than that of the upper groove 212. The side of the upper groove 212 near the connecting hole 221 is aligned with the side of the lower groove 212 near the connecting hole 221. The lower side of the upper groove 212 is connected to the upper side of the lower groove 212.

[0038] Furthermore, such as Figure 2 and 5 As shown, the combined sealing ring 3 includes at least: an open sealing outer ring 31 and an O-ring sealing inner ring 32; the open sealing outer ring 31 includes: an upper sealing plate 311, a side sealing plate 312, and a lower sealing plate 313. One end of the upper sealing plate 311 is connected to one end of the side sealing plate 312, and one end of the lower sealing plate 313 is connected to the other end of the side sealing plate 312, forming an open structure after connection; a sealing protrusion 314 is provided on the side of the side sealing plate 312 away from the upper sealing plate 311, and the sealing protrusion 314 is located at the end of the side sealing plate 312 close to the upper sealing plate 311; the O-ring sealing inner ring 32 is disposed within the open structure; in use, the lower sealing plate 313 and the side sealing plate 312 are... The portion of 12 without the sealing protrusion 314 and a portion of the O-ring inner ring 32 are both located in the lower groove 212. The portions of the upper sealing plate 311 and the side sealing plate 312 with the sealing protrusion 314 and a portion of the O-ring inner ring 32 are both located in the upper groove 211. After the bolts pass through the bolt through hole 131 and the connecting hole 221 to fasten the manhole flange cover 1 and the manhole flange 2, the tenon structure 11 is located in the upper groove 211 and contacts the upper side of the upper sealing plate 311. The side of the sealing protrusion 314 away from the side sealing plate 312 contacts the side of the upper groove 211 away from the connecting hole. The O-ring inner ring 32 deforms adaptively due to compression.

[0039] Specifically, the combined sealing ring 3 can be an integral structure or a separate structure. The combined sealing ring 3 has self-adaptive sealing surface performance, and the overall structure has high pressure resistance and reliable sealing performance. Its sealing principle is as follows: the bolts pass through the bolt through hole 131 and the connecting hole 221 in sequence to fasten the manhole flange cover 1 and the manhole flange 2. When the bolts are tightened, the pressure of the upper flange ring 13 and the lower flange ring 22 applies force to the combined sealing ring 3. The O-ring inner ring 32 of the combined sealing ring 3 is compressed and deforms adaptively. The contact area between the open sealing outer ring 31 and the O-ring inner ring 32 increases, and the contact area of ​​the sealing surface between the sealed upper flange ring 13 and the lower flange ring 22 increases. When the tightening force reaches the preset value, a sealing pressure that can prevent the medium from leaking is formed on the combined sealing ring 3, thereby making the manhole flange seal leak-proof.

[0040] Furthermore, the outer sealing ring 31 of the opening is made of polytetrafluoroethylene (PTFE) material with low-temperature resistance, but is not limited to PTFE material with low-temperature resistance. In this application, PTFE material with low-temperature resistance is preferred.

[0041] Specifically, the outer sealing ring 31 is made of polytetrafluoroethylene (PTFE), which has excellent low-temperature resistance (260℃~-260℃). This material not only has excellent weather resistance but also excellent chemical corrosion resistance.

[0042] Furthermore, the inner O-ring 32 is an O-ring with a metal spring skeleton rubber ring, but is not limited to an O-ring with a metal spring skeleton rubber ring. In this application, an O-ring with a metal spring skeleton rubber ring is preferred.

[0043] Specifically, the inner part of the O-ring with a metal spring skeleton is an O-ring with a metal spring skeleton, and the outer part of the O-ring with a metal spring skeleton is adhered with a certain thickness of elastic special rubber, wherein the special rubber is an existing elastic material. The O-ring inner ring 32 has good resilience and elongation. The O-ring inner ring 32 does not harden or become brittle in a cryogenic working environment and still has excellent resilience. At the same time, under the extrusion and rebound force of the sealing inner ring, it can ensure an increase in the contact area of ​​the sealing surfaces of the combined sealing ring 3 with the upper flange ring 13 and the lower flange ring 22, and ensure a tight fit.

[0044] The beneficial effects achieved by this application are as follows:

[0045] (1) The manhole flange sealing structure for rocket cryogenic storage tanks in this application adopts a stepped tenon and groove sealing structure. The boss tenon and the trapezoidal groove can ensure that the flange is easy to align during installation and can effectively prevent the sealing ring from being squeezed out of the sealing surface.

[0046] (2) The manhole flange sealing structure for rocket cryogenic storage tanks in this application eliminates the flange neck structure commonly used in general flanges, and designs the thickness of the upper / lower flange rings according to the load-bearing capacity. The end faces of the upper / lower flange rings are fitted together. This structure can minimize the weight of the manhole flange, while the fitted assembly increases the overall rigidity of the manhole flange, so that the coefficient of the flange structure is minimized.

[0047] (3) The combined sealing ring of this application does not harden or become brittle in a cryogenic working environment and still has excellent resilience. At the same time, under the extrusion and rebound force of the inner sealing ring, it can increase the contact area between the sealing ring and the flange sealing surface and ensure tight contact.

[0048] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the scope of protection of this application is intended to include the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0049] It is obvious that those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if these modifications and variations of this application fall within the scope of protection of this application and its equivalents, this application also intends to include these modifications and variations.

Claims

1. A manhole flange sealing structure for a rocket cryogenic storage tank, characterized in that, include: Manhole flange cover, manhole flange, combination sealing ring with self-adaptive sealing surface performance, and bolts; The sealing surface of the manhole flange cover is provided with a tenon structure; The sealing surface of the manhole flange is provided with a stepped groove structure; The combined sealing ring is set within the stepped groove structure; During connection, the sealing surface of the manhole flange cover contacts the sealing surface of the manhole flange, the tenon structure is located in the stepped groove structure and contacts the combined sealing ring, and the manhole flange cover and the manhole flange are fastened together by bolts. The manhole flange cover includes at least: a convex head and an upper flange ring; The upper flange ring is located around the convex head; The upper flange ring is provided with multiple bolt through holes; The bottom of the upper flange ring is used as the sealing surface, and at least one tenon structure is provided on the sealing surface; The manhole flange includes at least: a lower flange ring and a tapered ring for connection with the housing; A tapered ring is positioned around the lower flange ring; The lower flange ring is provided with multiple connection holes; The top of the lower flange ring is used as the sealing surface, and at least one stepped groove structure is opened on the sealing surface; The stepped groove structure includes at least an upper groove and a lower groove. The cross-sectional width of the lower groove is smaller than that of the upper groove. The side of the upper groove near the connecting hole is aligned with the side of the lower groove near the connecting hole. The lower side of the upper groove is connected to the upper side of the lower groove. The combined sealing ring includes at least: an open sealing outer ring and an O-ring sealing inner ring; The open sealing outer ring includes: an upper sealing plate, a side sealing plate and a lower sealing plate. One end of the upper sealing plate is connected to one end of the side sealing plate, and one end of the lower sealing plate is connected to the other end of the side sealing plate. After connection, an open structure is formed. A sealing protrusion is provided on the side of the side sealing sheet away from the upper sealing sheet, and the sealing protrusion is located at the end of the side sealing sheet close to the upper sealing sheet; The inner O-ring is positioned within the open structure; When in use, the parts of the lower sealing sheet and side sealing sheet without sealing protrusions and a part of the inner ring of the O-ring are all located in the lower groove, while the parts of the upper sealing sheet and side sealing sheet with sealing protrusions and a part of the inner ring of the O-ring are all located in the upper groove. After the bolts pass through the bolt through holes and the connection holes to fasten the manhole flange cover and the manhole flange, the tenon structure is located in the upper groove and contacts the upper side of the upper sealing plate. The side of the sealing protrusion away from the side sealing plate contacts the side of the upper groove away from the connection hole. The inner ring of the O-ring seal deforms adaptively due to compression.

2. The manhole flange sealing structure for a rocket cryogenic storage tank according to claim 1, characterized in that, The tenon structure is located on the sealing surface between the bolt hole and the convex head.

3. The manhole flange sealing structure for a rocket cryogenic storage tank according to claim 1, characterized in that, The tenon structure is a protrusion with a rectangular cross-section.

4. The manhole flange sealing structure for a rocket cryogenic storage tank according to claim 1, characterized in that, The stepped groove structure is located on the sealing surface on the side of the connection hole away from the conical ring.

5. The manhole flange sealing structure for a rocket cryogenic storage tank according to claim 1, characterized in that, The outer sealing ring of the opening is made of polytetrafluoroethylene material with low-temperature resistance.

6. The manhole flange sealing structure for a rocket cryogenic storage tank according to claim 1, characterized in that, The inner ring of the O-ring seal is an O-ring with a metal spring skeleton and a rubber ring.

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