A combined seal, a manufacturing method thereof, and a sealing structure

Abstract

The present invention belongs to the field of sealing technology, and specifically relates to a combined seal, a manufacturing method thereof, and a sealing structure. The combined seal includes a first support ring, a second support ring, a first graphite ring, a second graphite ring, and an alloy ring. The first graphite ring and the second graphite ring are configured to respectively perform sealing operations on the first sealing surface and the second sealing surface, and the alloy ring is configured to melt in response to an increase in temperature, thereby generating a radial force on the first graphite ring and the second graphite ring under the axial extrusion of the first support ring and the second support ring, thereby enhancing the sealing effect on the first sealing surface and the second sealing surface. The combined seal according to the present invention can meet the relevant requirements for sealing in high-temperature and high-pressure environments, and can also be applied to low-speed dynamic sealing occasions, and has good application prospects in this technical field.

Description

Technical Field

[0001] The present invention belongs to the technical field of sealing, and in particular relates to a combined sealing component, a manufacturing method thereof, and a sealing structure. Background Art

[0002] With the in-depth development of unconventional oil and gas resources, geological conditions and construction conditions are becoming increasingly complex, placing increasing demands on the sealing performance of downhole testing and operating tools. Under extreme operating conditions, downhole temperatures can reach 350°C or even higher, and sealing pressures are often also high, reaching 50 MPa or more. The sealing problem under high-temperature and high-pressure conditions has not been effectively addressed.

[0003] Most existing seals are based on rubber elements, but the long-term stable operating temperature of rubber element seals is limited. Even the perfluoroelastomer with the best temperature resistance currently available has a long-term stable operating temperature of less than 300°C, so it cannot adapt to higher operating ambient temperatures.

[0004] Various sealing methods based on all-metal sealing elements (such as O- and C-shaped metal rings) can withstand high temperatures, but due to the poor resilience of metal seals, a high degree of excitation force is required. To ensure a reliable seal, extremely high precision is required in the processing and installation of metal sealing elements and structures. Furthermore, metal-on-metal sealing surfaces face a difficult conflict between contact stress and contact wear. Wear is difficult to compensate for, leading to seal failure. Therefore, metal seals are currently typically used only in static sealing applications. Summary of the Invention

[0005] In order to solve part or all of the problems in the prior art, the present invention provides a combined seal, a manufacturing method thereof and a sealing structure.

[0006] According to a first aspect of the present invention, a modular seal is provided.

[0007] The combined seal comprises:

[0008] A first supporting ring includes a first main body and a first protrusion provided on a lower surface of the first main body;

[0009] a second supporting ring comprising a second main body and a second protruding portion disposed on an upper surface of the second main body and opposite to the first protruding portion;

[0010] a first graphite ring, disposed on the outer sides of the first protrusion and the second protrusion;

[0011] a second graphite ring, disposed inside the first protrusion and the second protrusion; and

[0012] The alloy ring is filled in the area surrounded by the first protrusion, the second protrusion, the first graphite ring and the second graphite ring.

[0013] The first graphite ring and the second graphite ring are configured to respectively seal the first sealing surface and the second sealing surface, and the alloy ring is configured to melt in response to an increase in temperature, thereby generating a radial force on the first graphite ring and the second graphite ring under axial compression by the first support ring and the second support ring, thereby enhancing the sealing effect on the first sealing surface and the second sealing surface.

[0014] As an extension of the above technical solution, the present invention further provides the following embodiments:

[0015] The first graphite ring and the second graphite ring are made of expanded graphite.

[0016] The density of the first graphite ring and the second graphite ring is within the range of 1.4-1.6 g / cm3.

[0017] The first support ring and the second support ring are configured such that, at the highest operating temperature, their outer diameters are at least 0.1 mm smaller than the inner diameter of the first sealing surface, and their inner diameters are at least 0.1 mm larger than the outer diameter of the second sealing surface.

[0018] The hardness of the first support ring and the second support ring is 50-100 HB lower than the hardness of the first sealing surface and the second sealing surface.

[0019] The melting point of the alloy ring is between 45°C and 70°C.

[0020] The alloy ring is made of tin-bismuth alloy or indium-tin-bismuth alloy.

[0021] According to a second aspect of the present invention, a method for manufacturing a combined sealing element is provided.

[0022] The manufacturing method of the combined seal comprises the following steps:

[0023] 1) providing the first graphite ring and the second graphite ring;

[0024] 2) providing the first support ring and the second support ring;

[0025] 3) pressing the first graphite ring and the second graphite ring into the first support ring / the second support ring;

[0026] 4) heating the alloy material to a molten state and injecting the alloy material into the cavity formed by the first graphite ring, the second graphite ring, and the first support ring / the second support ring;

[0027] 5) pressing the second support ring / the first support ring before the alloy material solidifies into the alloy ring;

[0028] 6) Keep the second support ring / the first support ring in a compressed state for at least half an hour.

[0029] According to a third aspect of the present invention, a sealing structure is provided.

[0030] The sealing structure comprises:

[0031] Not less than two combined seals as described above;

[0032] A butterfly spring disposed between two adjacent combined seals; and

[0033] A locking ring is connected to the first sealing member / the second sealing member and abuts against the uppermost combined sealing member and applies a pre-tightening force to the uppermost combined sealing member.

[0034] As an extension of the above technical solution, the present invention further provides the following embodiments:

[0035] The disc spring is configured such that its outer diameter is at least 0.5 mm smaller than the inner diameter of the first sealing surface, and its inner diameter is at least 0.5 mm larger than the outer diameter of the second sealing surface.

[0036] The advantages of the present invention compared to the prior art are:

[0037] (1) Compared with the rubber sealing method, the combined seal according to the present invention is made of graphite material and metal material, can withstand temperatures of 350°C or higher for a long time, can be applied to the sealing requirements in high-temperature working environments, and the sealing pressure can reach 50 MPa or above.

[0038] (2) Compared with metal sealing methods, the graphite material in the combined seal according to the present invention has higher compression resilience and smaller stress relaxation rate, and also has good self-lubrication. When used with a butterfly spring, it can not only be used for static sealing in high temperature and high pressure environments, but also can adapt to low-speed dynamic sealing occasions, and causes little wear on the sealing surface.

[0039] (3) The graphite material in the combined seal and sealing structure according to the present invention has excellent corrosion resistance, radiation resistance and thermal stability, and can be adapted to the sealing of various fluid media. Its application range is wider than that of metal seals.

[0040] (4) The combined seal and sealing structure according to the present invention have lower requirements on the processing and installation accuracy of the sealing surface than metal seals, have low sealing excitation force, and are more convenient and quick to install and use.

[0041] (5) The combined seal and the sealing structure according to the present invention have low cost of materials used, are simple to manufacture, and are suitable for mass production and use. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 A schematic structural diagram of a sealing structure according to the present invention;

[0043] Figure 2 A schematic diagram of a partial structure of a combined seal according to the present invention;

[0044] Figure 3 It is a schematic diagram of the local structure of the butterfly spring according to the present invention.

[0045] All drawings in the present invention are schematic diagrams for illustrating structures and principles, and are not necessarily drawn according to actual sizes and proportions.

[0046] The specific meanings of the reference numerals in the figures are as follows:

[0047] 1. First support ring; 11. First body; 12. First protrusion; 2. Second support ring; 21. Second body; 22. Second protrusion; 3. First graphite ring; 4. Second graphite ring; 5. Alloy ring; 6. First seal; 61. First sealing surface; 7. Second seal; 71. Second sealing surface; 8. Belleville spring; 9. Locking ring; 100. Combined seal; 200. Sealing structure. DETAILED DESCRIPTION

[0048] The embodiments of the present invention will be described in more detail below with reference to the accompanying drawings.

[0049] According to a first aspect of the present invention, a modular seal is provided.

[0050] like Figure 1 and Figure 2As shown, the combined seal 100 according to the present invention includes a first support ring 1, a second support ring 2, a first graphite ring 3, a second graphite ring 4, and an alloy ring 5. The first support ring 1 includes a first body 11 and a first protrusion 12 disposed on the lower surface of the first body 11. The second support ring 1 includes a second body 2 and a second protrusion 22 disposed on the upper surface of the second body 21 and opposite the first protrusion 12. The first graphite ring 3 is disposed outside the first and second protrusions 12, 22, while the second graphite ring 4 is disposed inside the first and second protrusions 12, 22. The alloy ring 5 fills the area surrounded by the first and second protrusions 12, 22, first and second graphite rings 3, 4. Furthermore, the first graphite ring 3 and the second graphite ring 4 are configured to respectively perform sealing operations on the first sealing surface 61 on the first sealing member 6 and the second sealing surface 71 on the second sealing member 7. The alloy ring 5 is configured to melt in response to an increase in temperature, thereby generating radial forces on the first graphite ring 3 and the second graphite ring 4 under the axial extrusion of the first support ring 1 and the second support ring 2, thereby enhancing the sealing effect on the first sealing surface 61 and the second sealing surface 71.

[0051] Through this design, firstly, the combined seal 100 according to the present invention can be heat-resistant and sealed for a long time in an operating environment where the external temperature reaches 350°C or higher, and the sealing pressure can reach 50MPa or above, thereby meeting the sealing requirements in a high-temperature and high-pressure working environment. Secondly, the graphite material in the combined seal 100 according to the present invention has excellent corrosion resistance, radiation resistance and thermal stability, and can be adapted to the sealing of a variety of fluid media, with a wider range of applications. Thirdly, the combined seal 100 according to the present invention has lower requirements for the processing and installation accuracy of the sealing surface than metal seals, has a low sealing excitation force, and is more convenient and quick to install and use. Thirdly, the graphite material in the combined seal according to the present invention has a high compression rebound elasticity and a low stress relaxation rate, and also has good self-lubrication, which can be applied to low-speed dynamic sealing occasions and causes little wear on the sealing surface. In addition, the material cost used in the combined seal 100 according to the present invention is low, and has good economy.

[0052] In one embodiment of the present invention, the first and second graphite rings 3 and 4 are made of expanded graphite. In addition to the excellent properties of natural graphite, such as heat and cold resistance, corrosion resistance, and self-lubrication, expanded graphite also offers unique characteristics, such as softness, high compression resilience, and strong adsorption. Using expanded graphite in the first and second graphite rings 3 and 4 fully utilizes its excellent properties, enhancing the sealing effect of the first and second seals 6 and 7.

[0053] Furthermore, in one embodiment of the present invention, the density of the first graphite ring 3 and the second graphite ring 4 is within the range of 1.4-1.6 g / cm³. This arrangement maximizes the flexibility and high compression resilience of expanded graphite, thereby enabling the combined seal according to the present invention to achieve optimal sealing performance.

[0054] like Figure 1 As shown, in one embodiment of the present invention, the first support ring 1 and the second support ring 2 are constructed so that, at the maximum operating temperature, their outer diameters are at least 0.1 mm smaller than the inner diameter of the first sealing surface 61, and their inner diameters are at least 0.1 mm larger than the outer diameter of the second sealing surface 71. This installation clearance can be calculated based on the thermal expansion coefficients of the materials used for the first support ring 1, the second support ring 2, the first seal 6, and the second seal 7, as well as the maximum operating temperature. This design prevents scraping or even locking of the first support ring 1 and the second support ring 2 with the first sealing surface 61 and the second sealing surface 71 due to thermal expansion at the maximum operating temperature, thereby protecting the first sealing surface 61 and the second sealing surface 71. It also ensures the independence of the combined seal 100, enabling its application in working environments requiring dynamic sealing.

[0055] In one embodiment of the present invention, the hardness of the first support ring 1 and the second support ring 2 is 50-100 HB lower than the hardness of the first sealing surface 61 and the second sealing surface 71. This design ensures that the first support ring 1 and the second support ring 2 have sufficiently high strength and hardness while also preventing scratches and damage to the first sealing surface 61 and the second sealing surface 71 that may be caused by the first support ring 1 and the second support ring 2 when they come into contact with the first sealing surface 61 and the second sealing surface 71 during installation, thereby protecting the first sealing surface 61 and the second sealing surface 71.

[0056] Preferably, the first support ring 1 and the second support ring 2 are made of stainless steel or tin bronze materials.

[0057] Preferably, when the sealing medium is highly corrosive, the first support ring 1 and the second support ring 2 are made of Hastelloy.

[0058] In one embodiment of the present invention, the melting point of the alloy ring 5 is between 45°C and 70°C. This configuration allows, on the one hand, the first support ring 1 and the second support ring 2 to be connected as a whole via the alloy ring 5 without requiring very high temperatures when manufacturing the combined seal 100, making the combined seal 100 relatively easy to form into a one-piece structure, thereby facilitating installation by construction personnel. On the other hand, during use, when the temperature rises, the alloy ring 5 can easily melt into a liquid state and expand in volume. The liquid alloy material formed by the melting of the alloy ring 5 generates a radial force through the axial extrusion of the first support ring 1 and the second support ring 2, and acts on the first graphite ring 3 and the second graphite ring 4, thereby quickly strengthening the sealing effect of the first sealing surface 61 and the second sealing surface 71.

[0059] Preferably, the alloy ring 5 is made of a tin-bismuth alloy or an indium-tin-bismuth alloy having a melting point of 45-70°C.

[0060] The combined seal 100 according to the present invention benefits from the composite use of graphite and metal materials. First, it is able to withstand heat and pressure for a long time in an operating environment where the external temperature reaches 350°C or higher and the sealing pressure reaches 50 MPa or higher, thereby meeting the sealing requirements in high-temperature and high-pressure working environments. Secondly, the graphite material in the combined seal 100 according to the present invention has excellent corrosion resistance, radiation resistance, and thermal stability, and can be adapted to seal a variety of fluid media, with a wider range of applications. Thirdly, the combined seal 100 according to the present invention has lower processing and installation precision requirements for the sealing surface than metal seals, making installation and use more convenient and quick, and the sealing excitation force is low. Thirdly, the graphite material in the combined seal according to the present invention has high compression rebound and low stress relaxation rate, and also has good self-lubrication, which makes it suitable for low-speed dynamic sealing applications and causes little wear on the sealing surface. In addition, the combined seal 100 according to the present invention uses low-cost materials and has good economic benefits.

[0061] According to a second aspect of the present invention, a method for manufacturing a combined sealing element is provided.

[0062] The manufacturing method of the combined seal comprises the following steps:

[0063] 1) providing a first graphite ring 3 and a second graphite ring 4;

[0064] 2) providing a first support ring 1 and a second support ring 2;

[0065] 3) Pressing the first graphite ring 3 and the second graphite ring 4 into the first support ring 1 / the second support ring 2;

[0066] 4) heating the alloy material to a molten state and injecting it into the cavity formed by the first graphite ring 3, the second graphite ring 4 and the first support ring 1 / the second support ring 2;

[0067] 5) Pressing the second support ring 2 / first support ring 1 into the alloy ring before the alloy material solidifies;

[0068] 6) Keep the second support ring 2 / first support ring 1 under pressure for at least half an hour.

[0069] In one embodiment of the present invention, the first graphite ring 3 and the second graphite ring 4 are provided in step 1) by pressing graphite through a mold, thereby manufacturing the required first graphite ring 3 and second graphite ring 4.

[0070] In one embodiment of the present invention, the first support ring 1 and the second support ring 2 are provided in step 2) by machining the selected metal material to produce the required first support ring 1 and the second support ring 2 .

[0071] The manufacturing method of the combined seal according to the present invention has clear steps and is simple and easy to implement. In addition, due to the setting of step 6), the yield is high, and the combined seal 100 according to the present invention is suitable for batch production.

[0072] According to a third aspect of the present invention, a sealing structure 200 is provided.

[0073] like Figure 1 As shown, the sealing structure 200 according to the present invention includes at least two combined seals 100 as described above, a disc spring 8 disposed between two adjacent combined seals 10, and a locking ring 9 connected to the first seal 6 / second seal 7 and abutting against the uppermost combined seal 100 to apply a pre-tightening force to the uppermost combined seal 100.

[0074] During operation, the combined seal 100 is disposed between the first sealing surface 61 and the second sealing surface 71. A butterfly spring 8 is disposed between two adjacent combined seals 100. A locking ring 9 is disposed above the uppermost combined seal 100, which is connected to the first seal 6 or the second seal 7 and can apply a preload force to the combined seal 100 in contact therewith. This preload force is transmitted downwardly through the butterfly spring 8 below the combined seal 100 to the combined seal 100 below the butterfly spring 8, and then in turn downwardly to the lowermost combined seal 100, thereby enabling the sealing structure 200 to seal the first sealing surface 61 and the second sealing surface 71 even in a room temperature environment. When the sealing structure 200 is in a high-temperature operating environment, the alloy ring 5 in the combined seal 100 melts and expands in volume, and under the action of the axial force applied by the first support ring 1 and the second support ring 2, a radial force is generated on the first graphite ring 3 and the second graphite ring 4 on both sides thereof, thereby enhancing the sealing effect on the first sealing surface 61 and the second sealing surface 71.

[0075] According to the sealing structure 200 of the present invention, the combined seal 100, the butterfly spring 8 and the locking ring 9 are used in combination, and the structure is stable and reliable. It is not only suitable for static sealing in high temperature and high pressure environments (external temperature reaches 350°C and above, and the sealing pressure reaches 50MPa and above), but also can adapt to low-speed dynamic sealing occasions, with little wear on the sealing surface, and has a relatively wide range of applications. In addition, the sealing structure 200 has lower requirements for the processing and installation accuracy of the sealing surface than metal seals, has a low sealing excitation force, and is more convenient and quick to install and use. In addition, because the sealing structure 200 includes the combined seal 100, the sealing structure 200 can also produce other technical effects that the combined seal 100 can produce, which will not be repeated here.

[0076] In one embodiment of the present invention, the outer diameter of the disc spring 8 is configured to be at least 0.5 mm smaller than the inner diameter of the first sealing surface 61, and at least 0.5 mm larger than the outer diameter of the second sealing surface 71. This design ensures that the disc spring 8 does not come into contact with the first and second sealing surfaces 61, 71 during operation of the sealing structure 200, thereby maintaining the independence of the sealing structure 200. While providing protection for the first and second sealing surfaces 61, 71, it also enables the sealing structure 200 to be successfully applied in operating environments requiring dynamic sealing.

[0077] In one embodiment of the present invention, in order to control the elastic force of the butterfly spring 8 within an appropriate range and ensure the smooth implementation of the sealing effect of the sealing structure 200, the butterfly spring 8 is made of thin spring steel, the thickness of a single sheet is about 0.5-1mm, and the compression stroke is about 1mm.

[0078] In one embodiment of the present invention, the sealing structure 200 includes three combined sealing elements 100 and two butterfly springs 8. This design is applicable to most sealing environments and can produce a good sealing effect.

[0079] In this application, the specific meanings of the terms "upper", "lower", "inner", "outer", "middle", "side" and so on when indicating directions are as follows: Figure 1 The drawing state of the middle sealing structure 200 is for reference.

[0080] Finally, it should be noted that while the present invention has been described in detail with reference to preferred embodiments, various modifications may be made and equivalent components may be substituted without departing from the scope of the present invention. In particular, the various technical features described in the various embodiments may be combined in any manner, provided there are no structural conflicts. The present invention is not limited to the specific embodiments disclosed herein, but encompasses all technical solutions within the scope of the claims.

Claims

1. A sealing structure comprising: Not less than two combined seals; A butterfly spring (8) provided between two adjacent combined seals; as well as A locking ring (9) connected to the first sealing member (6) / the second sealing member (7) and abutting against the uppermost combined sealing member and applying a pre-tightening force to the uppermost combined sealing member, The combined seal comprises: A first supporting ring (1) comprises a first main body (11) and a first protruding portion (12) provided on a lower surface of the first main body (11); A second supporting ring (2) comprising a second main body (21) and a second protruding portion (22) disposed on an upper surface of the second main body (21) and opposite to the first protruding portion (12); a first graphite ring (3) disposed outside the first protrusion (12) and the second protrusion (22); a second graphite ring (4) disposed inside the first protrusion (12) and the second protrusion (22); and The alloy ring (5) is filled in the area surrounded by the first protrusion (12), the second protrusion (22), the first graphite ring (3) and the second graphite ring (4). The first graphite ring (3) and the second graphite ring (4) are configured to respectively perform sealing operations on the first sealing surface (61) of the first sealing member (6) and the second sealing surface (71) of the second sealing member (7); the alloy ring (5) is configured to melt in response to a temperature increase, thereby generating a radial force on the first graphite ring (3) and the second graphite ring (4) under the axial compression of the first support ring (1) and the second support ring (2), thereby enhancing the sealing effect on the first sealing surface (61) and the second sealing surface (71).

2. The sealing structure according to claim 1, wherein: The first graphite ring (3) and the second graphite ring (4) are made of expanded graphite.

3. The sealing structure according to claim 2, wherein: The density of the first graphite ring (3) and the second graphite ring (4) is between 1.4 and 1.6 g / cm 3 within the scope of.

4. The sealing structure according to claim 3, wherein: The first support ring (1) and the second support ring (2) are configured such that, at the highest operating temperature, their outer diameters are at least 0.1 mm smaller than the inner diameter of the first sealing surface (61), and their inner diameters are at least 0.1 mm larger than the outer diameter of the second sealing surface (71).

5. The sealing structure according to claim 4, characterized in that: The hardness of the first support ring (1) and the second support ring (2) is 50-100 HB lower than the hardness of the first sealing surface (61) and the second sealing surface (71).

6. The sealing structure according to any one of claims 1 to 5, characterized in that: The melting point of the alloy ring (5) is between 45°C and 70°C.

7. The sealing structure according to claim 6, characterized in that: The alloy ring (5) is made of tin-bismuth alloy or indium-tin-bismuth alloy.

8. The sealing structure according to claim 1, wherein: The butterfly spring (8) is constructed such that its outer diameter is at least 0.5 mm smaller than the inner diameter of the first sealing surface (61), and its inner diameter is at least 0.5 mm larger than the outer diameter of the second sealing surface (71).

9. A method for manufacturing the combined seal in the sealing structure according to any one of claims 1 to 8, comprising the following steps: 1) Providing the first graphite ring (3) and the second graphite ring (4); 2) providing the first support ring (1) and the second support ring (2); 3) pressing the first graphite ring (3) and the second graphite ring (4) into the first support ring (1) / the second support ring (2); 4) heating the alloy material to a molten state and injecting the alloy material into the cavity formed by the first graphite ring (3), the second graphite ring (4) and the first support ring (1) / the second support ring (2); 5) pressing the second support ring (2) / the first support ring (1) before the alloy material solidifies into the alloy ring (5); 6) Maintaining the second support ring (2) / the first support ring (1) in a compressed state for at least half an hour.

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