A dual-empowered multi-level sealing ring for a cryogenic butterfly valve

Abstract

The present invention relates to a multi-level sealing ring with dual energy for cryogenic butterfly valves, which includes a highly elastic sealing ring and a negative thermal expansion sealing ring core. The highly elastic sealing ring includes a highly elastic upper sealing ring and a highly elastic lower sealing ring. The three metal rings of the highly elastic upper sealing ring, the negative thermal expansion sealing ring core, and the highly elastic lower sealing ring are stacked in sequence to form a multi-level sealing ring. The thermal expansion coefficient range of the multi-level sealing ring is -9.43 to 6.6×10 ‑6 mm / mm / °C; the highly elastic sealing ring is made of shape memory alloy, and the negative thermal expansion sealing ring core is made of negative thermal expansion alloy. The materials involved in the present invention do not cause low-temperature brittle failure; the organizational structure of the materials is stable, which can prevent adverse volume changes caused by low-temperature phase transformation, will not increase organizational stress, and will not cause warping deformation of the sealing surface that originally meets the sealing requirements after grinding, resulting in sealing failure.

Description

Technical Field

[0001] The invention belongs to the technical field of valve sealing, and relates to a multi-level sealing ring with dual empowerment for cryogenic butterfly valves. Background Art

[0002] The sealing ring is a key component for the sealing of cryogenic butterfly valves. The sealing quality problems need to be solved from the following aspects: 1) Selection of materials for each component: The materials should not cause low-temperature brittle failure; the organizational structure of the materials should be stable to prevent volume changes caused by low-temperature phase transformation, thereby preventing the increase of tissue stress and warping deformation of the sealing surface that originally meets the sealing requirements after grinding, resulting in sealing failure. 2) Increase the low-temperature elasticity of the sealing pair (starting from the aspects of materials and structures). 3) Avoid sealing failure and jamming phenomena caused by thermal expansion and contraction of components. Summary of the Invention

[0003] The purpose of the invention is to provide a multi-level sealing ring with dual empowerment for cryogenic butterfly valves, where the involved materials do not cause low-temperature brittle failure; the organizational structure of the materials is stable, which can prevent adverse volume changes caused by low-temperature phase transformation, will not increase tissue stress, and will not cause warping deformation of the sealing surface that originally meets the sealing requirements after grinding, resulting in sealing failure.

[0004] According to the technical solution provided by the invention: A multi-level sealing ring with dual empowerment for cryogenic butterfly valves includes a high-elastic sealing ring and a negative thermal expansion sealing ring core. The high-elastic sealing ring includes a high-elastic upper sealing ring and a high-elastic lower sealing ring. The three metal rings of the high-elastic upper sealing ring, the negative thermal expansion sealing ring core, and the high-elastic lower sealing ring are sequentially stacked to form a multi-level sealing ring; the thermal expansion coefficient range of the multi-level sealing ring is -9.43 to 6.6×10 -6 mm / mm / °C; the high-elastic sealing ring is made of shape memory alloy, and the negative thermal expansion sealing ring core is made of negative thermal expansion alloy.

[0005] As a further improvement of the invention, the high-elastic sealing ring is made of Ni 48.25 Ti 48.25 Fe 3.5 shape memory alloy.

[0006] As a further improvement of the invention, the negative thermal expansion sealing ring core is made of Hf 0.87 Ta 0.13 Fe2 negative thermal expansion alloy.

[0007] As a further improvement of the invention, the sealing surface of the multi-level sealing ring made by laminating and bonding the high-elastic upper sealing ring, the negative thermal expansion sealing ring core, and the high-elastic lower sealing ring is processed into an inclined conical surface.

[0008] As a further improvement of the present invention, a multi-level sealing ring with dual energization for a cryogenic butterfly valve is sleeved on the rotatable disc of the cryogenic butterfly valve to form a sealing pair with the seat of the cryogenic butterfly valve.

[0009] As a further improvement of the present invention, the high-elastic upper sealing ring, the negative thermal expansion sealing ring core and the high-elastic lower sealing ring are bonded with a high-performance cryogenic structural adhesive.

[0010] The positive and progressive effects of this application are as follows:

[0011] 1. The materials involved in the present invention do not cause brittle failure at low temperatures; the organizational structure of the materials is stable, which can prevent adverse volume changes caused by low-temperature phase transformation, will not increase tissue stress, will not cause warping deformation of the sealing surface that originally meets the sealing requirements after grinding, and will not cause sealing failure.

[0012] 2. The present invention selects a shape memory alloy and utilizes its superelasticity at ultra-low temperatures to solve the low-temperature elasticity problem of the sealing pair.

[0013] 3. The present invention selects a shape memory alloy and utilizes its high hardness to solve the problem of friction and wear resistance of the sealing pair.

[0014] 4. The present invention selects a negative thermal expansion sealing ring core, and by selecting the thickness of the negative thermal expansion sealing ring core, the overall thermal expansion coefficient of the sealing ring assembly (multi-level sealing ring) can be adjusted. During actual use, the corresponding comprehensive thermal expansion coefficient component can be selected according to specific needs, which can avoid sealing failure and jamming phenomena caused by thermal expansion and contraction of parts.

[0015] 5. The present invention combines and uses a shape memory alloy and a negative thermal expansion sealing ring core at the same time, giving full play to the advantages and unique properties of each material and solving the technical problems that cannot be completely solved by a single material. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a top view of the sealing ring assembly.

[0017] Figure 2 It is a front view of the sealing ring assembly.

[0018] Figure 3 For Figure 2 The enlarged schematic diagram of I in DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the drawings and in combination with the embodiments.

[0020] To enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0021] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned accompanying drawings are used to distinguish similar objects, and do not necessarily need to be used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so as to describe the embodiments of the present invention here. In addition, similar terms such as "comprising" and "having" mean that in addition to the content already listed in "comprising" and "having", other content not yet listed can also be "comprised" and "had". For example, a process, method, system, product or device that can include a series of steps or units does not necessarily have to be limited to those steps or units that have been clearly listed, but can include other steps or units that have not been clearly listed or are inherent to these processes, methods, products or devices.

[0022] Figures 1 to 3 It includes a shape memory alloy high-elastic sealing ring 1, a negative thermal expansion sealing ring core 2, etc.

[0023] Such as Figure 3 As shown, the present invention is a double-empowered multi-level sealing ring for a cryogenic butterfly valve, which includes a high-elastic sealing ring 1 and a negative thermal expansion sealing ring core 2. The high-elastic sealing ring 1 includes a high-elastic upper sealing ring 1-1 and a high-elastic lower sealing ring 1-2. The high-elastic upper sealing ring 1-1, the negative thermal expansion sealing ring core 2, and the high-elastic lower sealing ring 1-2 are sequentially stacked to form an upper, middle, and lower multi-level sealing ring; the thermal expansion coefficient range of the multi-level sealing ring is -9.43 to 6.6×10 -6 mm / mm / °C; the high-elastic sealing ring 1 is made of shape memory alloy, and the negative thermal expansion sealing ring core 2 is made of negative thermal expansion alloy.

[0024] The high-elastic sealing ring 1 is made of Ni 48.25 Ti 48.25 Fe 3.5 shape memory alloy; the negative thermal expansion sealing ring core 2 is made of Hf 0.87 Ta 0.13 Fe2 negative thermal expansion alloy.

[0025] The high-elastic sealing ring 1 includes a high-elastic upper sealing ring 1-1 and a high-elastic lower sealing ring 1-2. The sealing surface of the multi-layer sealing ring made by laminating and bonding the high-elastic upper sealing ring 1-1, the negative thermal expansion sealing ring core 2 and the high-elastic lower sealing ring 1-2 is processed into an inclined conical surface.

[0026] The double-empowered multi-layer sealing ring sleeve for cryogenic butterfly valves is sleeved on the rotatable disc of the cryogenic butterfly valve and forms a sealing pair with the seat of the cryogenic butterfly valve.

[0027] The high-elastic sealing ring 1 and the negative thermal expansion sealing ring core 2 are bonded with a high-performance low-temperature structural adhesive.

[0028] Ni 48.25 Ti 48.25 Fe 3.5 The average thermal expansion coefficient of the shape memory alloy is 6.6×10 -6 mm / mm / ℃ in the temperature range of -196℃ to 21℃, Hf 0.87 Ta 0.13 The average thermal expansion coefficient of the Fe2 negative thermal expansion alloy is -16.3×10 -6 mm / mm / ℃. When the negative thermal expansion sealing ring core 2 accounts for 50% of the dimension in the thickness direction, the calculated thermal expansion coefficient of the sealing ring assembly is -4.85×10 -6 mm / mm / ℃. When the negative thermal expansion sealing ring core 2 accounts for 40% of the dimension in the thickness direction, the calculated thermal expansion coefficient of the sealing ring assembly is -2.56×10 -6 mm / mm / ℃. When the negative thermal expansion sealing ring core 2 accounts for 30% of the dimension in the thickness direction, the calculated thermal expansion coefficient of the sealing ring assembly is -0.27×10 -6 mm / mm / ℃. The thermal expansion coefficients of the sealing ring assemblies with other different thickness ratios are shown in the following table.

[0029] The upper and lower layers of the sealing ring assembly are made of shape memory alloy materials, and the middle layer is made of negative thermal expansion alloy materials. The ratio of the dimension of the negative thermal expansion sealing ring core 2 in the thickness direction is determined according to the total thickness requirement and the overall thermal expansion coefficient requirement of the sealing ring assembly. The total thickness of the sealing ring assembly is determined by the design parameters of the butterfly valve sealing pair, and the overall thermal expansion coefficient of the sealing ring assembly is determined by the finite element simulation of the temperature field and stress field of the butterfly valve and further verified by experiments. According to the present invention, a series of sealing ring assemblies with different thermal expansion coefficients can be prepared, and the thermal expansion coefficient ranges from -9.43 to 6.6×10 -6 mm / mm / ℃. When the thermal expansion coefficient of the assembly is approximately 0, it is a near-zero expansion coefficient material. When the thermal expansion coefficient of the assembly is negative, it is a negative thermal expansion coefficient material, that is, the material not only does not shrink at low temperature, but also expands to a certain extent, which undoubtedly significantly improves the sealing performance of the sealing pair.

[0030] Ni48.25 Ti 48.25 Fe 3.5 The microhardness of the shape memory alloy material is between HRC40 and HRC45. This hardness is beneficial to improving the wear resistance and service life of the sealing pair. Ni that has been pre-deformed 48.25 Ti 48.25 Fe 3.5 When the shape memory alloy tends to recover its original shape during the unloading process, the strain value that can be recovered generally reaches 6-7%, that is, it is one order of magnitude higher than the elastic strain value of ordinary materials. Select Ni 48.25 Ti 48.25 Fe 3.5 The shape memory alloy material solves the problems of low-temperature elasticity and wear resistance.

[0031] Ni 48.25 Ti 48.25 Fe 3.5 The shape memory alloy can be prepared by vacuum non-consumable arc melting method using Ni, Ti and Fe with a purity of 99.99%. In a vacuum non-consumable arc melting furnace equipped with a water-cooled copper crucible, melting is carried out using high-purity argon with a purity of 99.9% as the protective gas. Adding Fe element on the basis of Ni and Ti elements is to obtain an alloy with higher hardness. The addition of 3.5% Fe element can obtain a higher hardness while the superelasticity of the alloy is not significantly reduced.

[0032] Hf as the intermediate layer of the sealing component 0.87 Ta 0.13 The Fe2 negative thermal expansion sealing ring core 2 can be replaced with other materials with negative thermal expansion properties, such as zirconium tungstate ZrW2O8, copper pyrophosphate and its doping system Cu 2-x A x P 2-y B y O7, etc. The overall thermal expansion coefficient of the sealing ring assembly can be designed according to the same principle, and then measured and corrected to a certain extent.

[0033] The above description of the embodiments is to enable those of ordinary skill in the art to understand and use the present invention. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative labor. Therefore, the present invention is not limited to the above embodiments, and the improvements and modifications made by those skilled in the art without departing from the scope of the present invention should be within the protection scope of the present invention.

[0034] Table 1 Thermal expansion coefficients of sealing ring assemblies with different thickness ratios

[0035] Thermal expansion coefficient unit (×10 -6 mm / mm / ℃)

[0036]

Claims

1. A multi-level sealing ring with dual empowerment for a cryogenic butterfly valve, characterized in that, It includes a highly elastic sealing ring (1) and a negative thermal expansion sealing ring core (2). The highly elastic sealing ring (1) includes a highly elastic upper sealing ring (1-1) and a highly elastic lower sealing ring (1-2). The three metal rings of the highly elastic upper sealing ring (1-1), the negative thermal expansion sealing ring core (2), and the highly elastic lower sealing ring (1-2) are stacked in sequence to form a multi-layer sealing ring. The thermal expansion coefficient range of the multi-layer sealing ring is -9.43 to 6.6×10 -6 mm / mm / ℃. The highly elastic sealing ring (1) is made of a shape memory alloy, and the negative thermal expansion sealing ring core (2) is made of a negative thermal expansion alloy. The highly elastic sealing ring (1) is made of Ni48.25Ti48.25Fe3.5 shape memory alloy. The negative thermal expansion sealing ring core (2) is made of Hf0.87Ta0.13Fe2 negative thermal expansion alloy.

2. The multi-level sealing ring with dual energization for cryogenic butterfly valves as described in claim 1, wherein, The sealing surface of the multi-layer sealing ring made by laminating and bonding a high-elasticity upper sealing ring (1-1), a negative thermal expansion sealing ring core (2), and a high-elasticity lower sealing ring (1-2) is machined into an inclined conical surface.

3. The double-empowered multi-level sealing ring for cryogenic butterfly valves as claimed in claim 1, wherein, The multi-layer sealing ring is sleeved on the rotatable disc of the cryogenic disc valve and forms a sealing pair with the seat of the cryogenic disc valve.

4. The dual-empowered multi-level sealing ring for cryogenic butterfly valve according to claim 1, characterized in that, The high-elasticity upper sealing ring (1-1), the negative thermal expansion sealing ring core (2), and the high-elasticity lower sealing ring (1-2) are bonded with a high-performance low-temperature structural adhesive.

Images