Mountain-shaped high-pressure self-tightening flange

Abstract

The present invention discloses a mountain-shaped high-pressure self-tightening flange, which has better high-temperature resistance and solves the problems in the prior art. The above-mentioned mountain-shaped high-pressure self-tightening flange includes a sleeve joint, a ferrule, bolts, nuts and a mountain-shaped sealing ring; the mountain-shaped sealing ring, the structure of its circumferential cross-section includes a triangular rib portion and double arms symmetrically arranged on both sides of the triangular rib portion; the joint of the upper surface of the triangular arm and the end surface away from the triangular rib portion is an arc surface, which is the sealing arc surface of the mountain-shaped sealing ring.

Description

Technical Field

[0001] The present invention relates to a brand-new mountain-shaped seal, specifically to a high-temperature-resistant mountain-shaped high-pressure self-tightening flange based on inconel (Inconel)-like materials, which is applied in fields such as deep-developed petroleum, petrochemical, chemical, coal chemical, shipbuilding, metallurgy, aviation, aerospace, military, national defense, and synthetic materials. Background Art

[0002] Flanges are pipe connectors and are essential for connecting industrial production devices, transportation projects, aerospace, national defense, military and other equipment and pipes, as well as for connecting between equipment. They are also general pipe fittings with a very large demand.

[0003] Traditional flanges can all be simplified to flat-weld flanges for force analysis. They adopt a forced sealing structure. Under the action of bolt pre-tightening force, the hardness of the sealing gasket and the gasket material is often lower than that of the flange. They are extruded and deformed, and the uneven micro-gaps on the flange sealing surface are filled. At the same time, a sealing pressure is formed on the sealing surface to achieve the sealing effect. The defects of traditional flanges are:

[0004] (1) During operation under pressure, the internal pressure of the pipeline will cause the sealing surface to relax along the pipeline direction, thereby reducing the sealing performance at the connection. Therefore, it is necessary to increase the bolt pre-tightening load during installation, which correspondingly increases the flange bending moment that the flange can withstand. So the structural size of the flange appears thick and large. Even so, it is impossible to avoid the serious defect that the sealing specific pressure of the flange connection in the working state is lower than that in the pre-tightening state.

[0005] (2) Since the connecting bolts are parallel to the pipeline direction, the additional loads generated in the pipeline system during operation, such as pipeline stretching and compression, pressure fluctuations, bending moments, torques, impacts, etc., will first be directly borne by the flange connecting bolts, which also leads to a decrease in the pre-tightening effect of the flange connection and affects the sealing performance of the connection.

[0006] (3) In actual engineering, due to the existence of loads such as temperature difference, bending moment, torque, impact, etc., the bolt force cannot be evenly distributed in the 360° direction, that is, when the effective sealing specific pressure on the sealing surface is damaged, an accident occurs.

[0007] This is the fundamental reason why it is difficult to completely prevent leakage in traditional flange pipeline systems (especially under high temperature and high pressure). Therefore, in modern fields such as petroleum, petrochemical, chemical, coal chemical, shipbuilding, metallurgy, aviation, aerospace, military, national defense, and synthetic materials, traditional flanges are used to connect pipes, and sealing is achieved by local plastic extrusion deformation of the sealing gasket. The reliability of the connection is poor, and problems such as leakage are likely to occur at the connection.

[0008] With the in-depth development of fields such as petroleum, petrochemical, chemical, coal chemical, shipbuilding, metallurgy, aviation, aerospace, military, national defense, and synthetic materials, traditional connection methods can no longer meet the demands of the times. Especially for high-temperature and high-pressure or cryogenic and high-pressure applications, new mechanical structures and special materials are required to meet real-time needs.

[0009] Chinese Patent Document 200720079783.2 discloses a high-pressure self-tightening flange, which is a Chinese patent application filed by the applicant for the company's product ZY-LOC. Its structure includes a ferrule, a sleeve joint, a T-shaped sealing ring, and bolts. In this structure, the T-shaped sealing ring is the core sealing component. The T-shaped sealing ring includes a rib in the middle, and on both sides of the rib are T-shaped arms. The T-shaped arms can effectively contract and expand under the forced extrusion of the sleeve joint to form an elastic seal. The T-shaped arms are evenly stressed at 360° under the extrusion of the sleeve joint. This is the reason why it does not leak. However, its sealing effect deteriorates under high-temperature conditions of about 800°C. After analysis, this is because the two arms of the T-shaped sealing ring are relatively thin, and at high temperatures, the stiffness is insufficient and it is prone to deformation.

[0010] Therefore, the applicant invented a new type of sealing form under conditions of high temperature (about 800°C), high pressure (about 20 MPa), and a material similar to inconel. Summary of the Invention

[0011] The purpose of the present invention is to provide a mountain-shaped high-pressure self-tightening flange, which is suitable for use at high temperatures and has strong resistance to deformation.

[0012] In order to achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0013] The mountain-shaped high-pressure self-tightening flange includes a sleeve joint, a ferrule, bolts, nuts, and a mountain-shaped sealing ring;

[0014] The mountain-shaped sealing ring, the circumferential cross-sectional structure of which includes a triangular rib portion for positioning and two symmetrically arranged arms on both sides of the triangular rib portion; the intersection of the upper surface of the arms and the end surface away from the triangular rib portion is an arc surface, which is the sealing arc surface of the mountain-shaped sealing ring and plays a sealing role. This structure has greater stiffness and is not easily deformed;

[0015] The mountain-shaped sealing ring is located between two sleeve joints, and the two sleeve joints clamp the triangular rib portion of the mountain-shaped sealing ring. There are two ferrules, one on the upper and one on the lower, and the two ferrules clamp the upper and lower ends of the two sleeve joints; under the action of the ferrules and the bolts and nuts for fastening the ferrules, the sleeve joints and the pipeline form a strong whole; there are sealing conical surfaces in the two sleeve joints that match the mountain-shaped sealing ring and jointly act with the sealing arc surface of the mountain-shaped sealing ring to form a seal.

[0016] As a preferred technical solution, the triangle of the rib portion is an isosceles triangle.

[0017] As a preferred technical solution, the mountain-shaped sealing ring is made of Inconel-like material.

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

[0019] The present invention provides a sealing ring with a brand-new structure - the mountain-shaped sealing ring. Its structure is the optimal mechanical structure obtained by mechanical modeling using Inconel material under the condition of 800 °C. It has stronger resistance to deformation at high temperatures, and the stress at the junction of the two arms and the rib of the mountain-shaped sealing ring is smaller. Therefore, it is more suitable for application under high-temperature conditions. Description of the Drawings

[0020] Figure 1 It is a schematic cross-sectional view of a mountain-shaped high-pressure self-tightening flange.

[0021] Figure 2 It is a schematic structural view of the circumferential cross-section of the mountain-shaped sealing ring.

[0022] Figure 3 It is a finite element model and mesh diagram of the mountain-shaped sealing ring.

[0023] Figure 4 It is a schematic diagram of the equivalent stress of the mountain-shaped sealing ring under an internal pressure of 20 MPa.

[0024] Figure 5 It is a schematic diagram of the contact stress of the mountain-shaped sealing ring under an internal pressure of 20 MPa.

[0025] Figure 6 It is a schematic diagram of the equivalent stress of the mountain-shaped sealing ring under an internal pressure of 30 MPa.

[0026] Figure 7 It is a schematic diagram of the contact stress of the mountain-shaped sealing ring under an internal pressure of 30 MPa.

[0027] Figure 8 It is a schematic diagram of the equivalent stress of the mountain-shaped sealing ring under an internal pressure of 40 MPa.

[0028] Figure 9 It is a schematic diagram of the contact stress of the mountain-shaped sealing ring under an internal pressure of 40 MPa.

[0029] Figure 10 It is a schematic diagram of the equivalent stress of the mountain-shaped sealing ring under an internal pressure of 50 MPa.

[0030] Figure 11 It is a schematic diagram of the contact stress of the mountain-shaped sealing ring under an internal pressure of 50 MPa.

[0031] Among them, the reference numerals are as follows:

[0032] 1 - Mountain-shaped sealing ring, 101 - Triangular rib portion, 102 - Arm, 103 - Sealing arc surface, 2 - Sleeve joint, 201 - Sealing conical surface, 3 - Ferrule, 4 - Bolt. Detailed implementation mode

[0033] The object of the present invention is to overcome the defects of the prior art and provide a mountain-shaped high-pressure self-tightening flange. The present invention will be further described in detail below with reference to the embodiments.

[0034] Embodiment

[0035] The mountain-shaped high-pressure self-tightening flange described in the present invention proposes a brand-new sealing method. It adopts a mountain-shaped sealing ring 1, which has better high-temperature resistance compared with the ZY-LOC high-pressure self-tightening flange of the same applicant company. Its structure is the best mechanical structure obtained through mechanical modeling under the conditions of high temperature (about 800 °C), high pressure (about 20 MPa), and the material inconel.

[0036] As Figure 1 shown, the mountain-shaped high-pressure self-tightening flange includes two sleeve joints 2, two ferrules 3, four bolts 4, eight spherical nuts, and a mountain-shaped sealing ring 1.

[0037] The mountain-shaped sealing ring 1, the structure of its circumferential cross-section is as Figure 2 shown, including a triangular rib portion 101 that plays a positioning role and two symmetric arms 102 on both sides of the triangular rib portion 101. The triangular rib portion 101 and the arms 102 cooperate to form the mountain-shaped sealing ring 1. The triangle of the rib portion is an isosceles triangle.

[0038] The upper surface of the triangular arm 102 and the end surface away from the triangular rib portion 101 are joined by an arc surface, which is the sealing arc surface 103 of the mountain-shaped sealing ring 1 and serves as a seal.

[0039] The mountain-shaped sealing ring 1 is located between two sleeve joints 2, as Figure 2 shown. There are two sleeve joints 2. The two sleeve joints 2 clamp the triangular rib portion 101 of the mountain-shaped sealing ring 1. There are two ferrules 3, one on the upper and one on the lower. The two ferrules 3 clamp the upper and lower ends of the two sleeve joints 2. Under the action of the ferrules 3, the sleeve joints 2 and the pipeline form a strong integral body. There is a sealing conical surface 201 in the two sleeve joints 2 that matches the mountain-shaped sealing ring 1 and jointly acts with the sealing arc surface 103 of the mountain-shaped sealing ring 1 to form a seal.

[0040] Two threaded holes are respectively arranged at both ends of the ferrule 3. The bolt 4 passes through the threaded holes, and the two ends of the bolt 4 are fixed with spherical nuts. The bolt 4 fixedly connects the two ferrules 3 located above and below the sleeve joint 2 into a whole. The axis of the bolt 4 is perpendicular to the axis of the sleeve joint 2.

[0041] Since the rib part has an isosceles triangle structure, the angle between the rib part and the double arms 102 is relatively large, and stress concentration is not easily formed.

[0042] Since the double arms 102 of the mountain-shaped seal ring 1 are thicker than those of the T-shaped seal ring of the ZY-LOC high-pressure self-tightening flange, the ability to resist deformation is stronger and it is not easily deformed at high temperatures.

[0043] The structure of the mountain-shaped seal ring 1 described in this embodiment is the best modeling mechanical structure obtained by mechanical modeling using Inconel material under the conditions of 800 °C and 20 MPa. When the process conditions change, Figure 2 in which the values of the parameters θ, S, R, H, and h will change.

[0044] During installation, first position the sleeve 2, use a non-abrasive material to remove the lubricating oil on the sealing conical surface 201 of the sleeve 2 and the surface of the mountain-shaped seal ring 1, then install the mountain-shaped seal ring 1 onto the sealing conical surface 201 of the sleeve 2, and keep a certain gap between the arm 102 of the mountain-shaped seal ring 1 and the end face of the sleeve 2. Use the ferrule 3 to sleeve the sleeve 2, apply a lubricant to the contact part between the ferrule 3 and the sleeve 2 to reduce friction. Insert the bolt 4 into the screw hole of the ferrule 3, put on and tighten the nut. After tightening the nut, the end faces of the two sleeves 2 and the rib part of the seal ring should be in close contact after installation.

[0045] The stress calculation of the mountain-shaped seal ring high-pressure self-tightening flange is as follows:

[0046] I. Calculation conditions, finite element model and mesh division

[0047] 1. Finite element model and mesh division The blind joint and the "mountain-shaped" seal ring are approximately simplified as left-right symmetric. Then, according to symmetry, 1 / 8 of the overall structure is taken for modeling, and the finite element model and mesh are Figure 3 as shown.

[0048] II. Displacement boundary conditions and loading

[0049] 1. Displacement boundary conditions

[0050] Symmetric displacement constraints are applied at the three symmetric planes.

[0051] 2. Loads The internal pressure is taken as 20 MPa, 30 MPa, 40 MPa, and 50 MPa respectively; a pre-tightening force is applied at the bolt holes; the bolt pre-tightening force is taken as: 5 kN for each bolt.

[0052] III. Calculation

[0053] 1. Internal pressure 20 MPa

[0054] When the bolt pre-tightening force is 5 kN, the equivalent stress of the mountain-shaped seal ring is as Figure 4 shown;

[0055] The maximum equivalent stress of the mountain-shaped seal ring is 60.74 MPa < [σ], so the strength of the "mountain-shaped" seal ring meets the requirements;

[0056] The contact stress is as Figure 5 shown, and the maximum contact stress is 77.1 MPa.

[0057] From Figure 5 it can be seen that on the sealing surface, the circumferential contact stress is evenly distributed and continuously changes along the width direction of the seal ring.

[0058] 2. Internal pressure 30 MPa

[0059] The equivalent stress of the mountain-shaped seal ring is as Figure 6 shown. The maximum equivalent stress is 91.2 MPa.

[0060] The contact stress of the mountain-shaped seal ring is as Figure 7 shown. On the sealing surface, the circumferential contact stress is evenly distributed and continuously changes along the width direction of the "mountain-shaped" seal ring, with a maximum of 115.6 MPa.

[0061] 3. Internal pressure 40 MPa

[0062] The equivalent stress of the mountain-shaped seal ring is as Figure 8 shown. The maximum equivalent stress is 121.7 MPa.

[0063] The contact stress of the mountain-shaped seal ring is as Figure 9 shown. On the sealing surface, the circumferential contact stress is evenly distributed and continuously changes along the width direction of the "mountain-shaped" seal ring, with a maximum of 154 MPa.

[0064] 4. Internal pressure 50 MPa

[0065] The equivalent stress of the mountain-shaped seal ring is as Figure 10 shown. The maximum equivalent stress is 152.3 MPa. The contact stress of the "mountain-shaped" seal ring is as Figure 11 shown. On the sealing surface, the circumferential contact stress is evenly distributed and continuously changes along the width direction of the "mountain-shaped" seal ring, with a maximum of 192.4 MPa.

[0066] IV. Result summary and conclusion

[0067]

[0068] Conclusion: From the stress and contact stress diagrams with internal pressures of 20 - 50 MPa, it can be seen that under a certain pre-tightening effect, the equivalent stress of the entire structure and the contact stress of the "mountain-shaped" seal ring both increase with the increase of the internal pressure.

[0069] According to the above embodiments, the present invention can be well implemented. It is worth noting that on the premise of the above structural design, in order to solve the same technical problems, even if some non-substantive changes or refinements are made to the present invention, the essence of the technical solutions adopted is still the same as that of the present invention, so it should also be within the protection scope of the present invention.

Claims

1. The mountain-shaped high-pressure self-tightening flange is characterized in that It includes a socket, a ferrule, a bolt, a spherical nut and a mountain-shaped sealing ring; The mountain-shaped sealing ring has a structure in its circumferential cross-section including a triangular rib portion and two arms symmetrically arranged on both sides of the triangular rib portion; the intersection of the upper surface of the triangular arm and its end surface away from the triangular rib portion is an arc surface, which is the sealing arc surface of the mountain-shaped sealing ring; The mountain-shaped sealing ring is located between two sockets. The two sockets clamp the triangular rib portion of the mountain-shaped sealing ring. There are two ferrules, one on the top and one on the bottom. The two ferrules clamp the upper and lower ends of the two sockets. Under the action of the ferrules, the bolts for fastening the ferrules and the spherical nuts, the sockets and the pipeline form a strong integral body; there is a sealing cone surface in the two sockets that matches the mountain-shaped sealing ring and jointly acts with the sealing arc surface of the mountain-shaped sealing ring to form a seal.

2. The chevron-shaped high-pressure self-tightening flange according to claim 1, wherein The triangle of the rib portion is an isosceles triangle.

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