Low-temperature anti-flutter one-way valve and liquid oxygen methane engine

Abstract

The invention provides a low-temperature anti-flutter one-way valve and a liquid oxygen methane engine. The low-temperature anti-flutter one-way valve at least comprises a shell and a blanking cap installed at the inlet end of the shell, and the blanking cap is axially provided with an opening communicated with the interior of the shell. The end, away from the plug, of the shell is an outlet, a sealing boss is arranged on the inner wall of the side, close to the outlet, of the shell, a first space is formed between the sealing boss and the plug, and the inner diameter of the side, close to the inlet, of the first space is larger than that of the other side. The valve element assembly is movably arranged in the first space, and an air hole communicating with the inlet and the outlet is formed in the valve element assembly. The outer wall of the first side of the valve element assembly is provided with a first outer diameter part and a second outer diameter part which are matched with the first space, and the first outer diameter is larger than the second outer diameter; the end of the second side of the valve element assembly is located at the outlet and matched with the sealing end face of the sealing boss. One end of the spring is mounted on one side, close to the inlet, of the valve element assembly, and the other end is matched with the back of the sealing end face of the sealing boss to generate acting force towards the inlet on the valve element assembly.

Description

Technical Field

[0001] The present invention relates to the technical field of space launch vehicles, and particularly to a cryogenic anti-flutter check valve and a liquid oxygen-methane engine. Background Art

[0002] The check valve is an important component of the self-pressurizing delivery system of a launch vehicle engine and plays an important role in the pressurization circuit. During performance tests, the check valve has experienced flutter phenomena many times. Especially when the engine operates under low working conditions, the medium flow rate is small and the inlet and outlet pressures are relatively low, so it is more likely to generate flutter problems, which affect the normal operation of the system and may even cause the valve itself to malfunction seriously.

[0003] Currently, there are several improved structures for the check valve flutter problem, such as increasing the damping structure by adding a bushing to the valve core, using a stainless steel spring coil or a corrugated belt expansion ring. However, these methods all have many problems. For example, using a bushing and a stainless steel spring coil is likely to generate debris or cause jamming, and the damping effect of using a corrugated belt expansion ring is unstable at normal and low temperatures.

[0004] Therefore, there is an urgent need to provide a check valve that can be applied to a low-temperature environment, avoid valve body flutter during operation, and improve the working performance and reliability of the valve. Summary of the Invention

[0005] To solve the above technical problems, the present invention provides a cryogenic anti-flutter check valve and a liquid oxygen-methane engine. By setting an unbalanced area on the inlet side, the check valve is sensitive to pressure but not to pressure difference, ensuring stable performance after the valve is opened, solving the flutter problem when the flow rate decreases, and avoiding debris brought to the downstream system due to valve jamming caused by flutter wear.

[0006] On one hand, the present invention provides a low-temperature anti-flutter check valve, which at least includes a plug, a housing, a valve core assembly and a spring; the plug is installed at one end of the housing inlet, and an opening communicating with the inside of the housing is axially provided thereon; the end of the housing away from the plug is the outlet, and a sealing boss is provided on the inner wall of the housing near the outlet side. A first space is formed between the sealing boss and the plug, and the inner diameter of the first space near the inlet side is larger than that of the other side; the valve core assembly is movably arranged in the first space, and an air hole communicating with the inlet and the outlet is provided therein; on the outer wall of the first side of the valve core assembly, there is a first outer diameter part adapted to the large inner diameter of the first space and a second outer diameter part adapted to the small inner diameter, and the first outer diameter is larger than the second outer diameter; the end of the second side of the valve core assembly is located at the outlet and cooperates with the sealing end face of the sealing boss; a first dynamic seal is provided between the first outer diameter part of the valve core assembly and the large inner diameter part of the housing, and a second dynamic seal is provided between the second outer diameter part of the valve core assembly and the small inner diameter part of the housing, and the diameter of the first dynamic seal is larger than that of the second dynamic seal; one end of the spring is installed on the side of the valve core assembly close to the inlet, and the other end is used to cooperate with the back of the sealing end face of the sealing boss to generate a force on the valve core assembly in the direction of the inlet.

[0007] In one embodiment, the valve core assembly includes a sleeve and a valve core; the outer wall of the sleeve adapts to the change of the inner diameter of the first space and is movably arranged in the first space. A first air hole for the medium to pass through is provided inside the sleeve. After the valve is opened, the first air hole communicates with the inlet and the outlet; an installation hole for the spring is axially provided on the sleeve, and the side of the spring away from the sealing boss is arranged in the spring installation hole; one side of the valve core is arranged inside the sleeve and fixedly connected to the inner wall of the sleeve, and the end of the other side is located at the outlet and cooperates with the sealing end face of the sealing boss.

[0008] In one embodiment, the first dynamic seal is a first sealing ring provided between the large inner diameter part of the housing and the sleeve, and the second dynamic seal is a second sealing ring provided between the small inner diameter part of the housing and the sleeve; the opening of the first sealing ring faces the inlet side, and the opening of the second sealing ring faces the outlet side.

[0009] In one embodiment, a second sealing member is provided on the end face of the valve core for cooperating with the sealing boss.

[0010] In one embodiment, the spool assembly further includes a gland fixedly arranged on the spool near the inlet side; one axial side of the gland presses the second sealing ring tightly between the housing and the sleeve, and the other side is matched with the plug cover; the gland is provided with a second air hole communicating the inlet and the first air hole.

[0011] In one embodiment, a retaining ring for defining the second sealing ring is arranged on the outer wall of the sleeve near the outlet side; the retaining ring is fixed to the outer wall of the sleeve through an internally placed steel wire.

[0012] In one embodiment, at least one annular groove is arranged on the outer wall of the sleeve between the first sealing ring and the second sealing ring, and a non-metallic support ring is arranged in the annular groove.

[0013] In any of the above embodiments, an exhaust port is radially opened at the position where the housing transitions from a large inner diameter part to a small inner diameter part.

[0014] In one embodiment, the plug cover is threadedly connected to the housing, and a third sealing member is arranged at the connection; the third sealing member is set as a static seal.

[0015] On the other hand, the present invention provides a liquid oxygen methane engine, which at least includes the cryogenic anti-chatter check valve in any one of the above embodiments.

[0016] The cryogenic anti-chatter check valve and the liquid oxygen methane engine provided by the present invention solve the chatter problem caused by the reduction of the flow rate after the valve is opened, thereby ensuring the stable performance of the product and increasing the stability of the product itself and the use system. The cryogenic anti-chatter check valve of the present invention has a simple structure and reliable performance. By arranging a non-metallic support ring at a suitable position near the spring energy storage sealing ring, the service life and sealing performance of the spring energy storage sealing ring are increased, and at the same time, the sticking problem at low temperature is solved, so that the check valve of the present invention can be applied to normal temperature and low temperature environments.

[0017] The cryogenic anti-chatter check valve and the liquid oxygen methane engine of the present invention use a cryogenic metal or non-metallic spring energy storage sealing ring to achieve dynamic sealing in a cryogenic environment, reducing the friction force while ensuring the sealing performance of the product.

[0018] After reading the specific embodiments and viewing the drawings, those skilled in the art will recognize additional features and advantages. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0020] Figure 1 It is a structural schematic diagram of the low-temperature anti-flutter check valve according to an embodiment of the present invention.

[0021] Figure 2 It is an overall structural schematic diagram of the low-temperature anti-flutter check valve according to an embodiment of the present invention. Detailed implementation manners

[0022] The following will describe in detail the features and exemplary embodiments of various aspects of the present invention. In order to make the purpose, technical solutions and advantages of the present invention clearer, the following will further describe the present invention in detail in combination with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described here are only configured to explain the present invention and are used to exemplarily illustrate the principle of the present invention, and are not configured to limit the present invention. In addition, the components in the drawings are not necessarily drawn to scale. For example, the sizes of some components or regions in the drawings may be enlarged for other components or regions to help understand the embodiments of the present invention.

[0023] The orientation terms appearing in the following description are all the directions shown in the drawings and do not specifically limit the structure of the embodiments of the present invention. In the description of the present invention, it should be noted that unless otherwise specified, the terms "installed", "connected", and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0024] In addition, the terms "including", "comprising", "having" or any other variant thereof are intended to cover non-exclusive inclusion, so that a series of elements, structural components or assemblies include not only those elements, but also other structural components or assemblies that are not explicitly listed or inherent to the structural components and assemblies. Without more limitations, the elements defined by the statement "including..." do not exclude the existence of additional identical elements in the articles or devices including the elements.

[0025] Spatial relationship terms such as "below", "beneath", "under", "lower", "above", "on", "higher", etc. are used for convenience of description to explain the positioning of one element relative to a second element, and these terms are intended to cover different orientations of the device in addition to orientations different from those shown in the figures. Additionally, for example, "one element is on / under another element" can mean that the two elements are in direct contact or that there are other elements between the two elements. Furthermore, terms such as "first", "second", etc. are also used to describe various elements, regions, parts, etc., and should not be construed as limiting. Similar terms denote similar elements throughout the description.

[0026] For those skilled in the art, the present invention can be implemented without some of these specific details. The following description of the embodiments is merely provided to better understand the present invention by showing examples of the present invention.

[0027] See Figure 1 and Figure 2 On the one hand, the present invention provides a low-temperature anti-flutter check valve, which at least includes: a plug cover 1, a housing 2, a valve core assembly 3, and a spring 4. The plug cover 1 is installed at one end of the housing inlet A, and an opening communicating with the inside of the housing 2 is axially provided thereon. The end of the housing 2 away from the plug cover 1 is the outlet B. A sealing boss 9 is provided on the inner wall of the housing 2 near the outlet B side. A first space is formed between the sealing boss 9 and the plug cover 1. The inner diameter of the first space on the side close to the inlet A is larger than that on the other side. The valve core assembly 3 and the spring 4 are arranged in the first space. Among them, the valve core assembly 3 is movably arranged in the first space, and air holes for communicating with the inlet A and the outlet B are provided inside the valve core assembly 3. The outer wall of the first side of the valve core assembly 3 has a first outer diameter portion adapted to the large inner diameter of the first space and a second outer diameter portion adapted to the small inner diameter. The first outer diameter is larger than the second outer diameter, so that the first end face area of the valve core assembly 3 facing the inlet A side is larger than the second end face area on the other side. The end of the second side of the valve core assembly 3 is located at the outlet B and cooperates with the sealing end face (the end face close to the outlet B side) of the sealing boss 9 to realize the opening and closing of the valve.

[0028] A first dynamic seal 51 is provided between the first outer diameter portion of the valve core assembly 3 and the large inner diameter portion of the housing 2, and a second dynamic seal 52 is provided between the second outer diameter portion of the valve core assembly 3 and the small inner diameter portion of the housing 2. The diameter of the first dynamic seal 51 is larger than that of the second dynamic seal 52.

[0029] One end of the spring 4 is installed on the side of the valve core assembly 3 close to the inlet A, and the other end is used to cooperate with the back surface (the end face close to the inlet A) of the sealing end face of the sealing boss 9 to generate a force on the valve core assembly 3 in the direction of the inlet A, so that the end of the other side of the valve core assembly 3 is tightly attached to the sealing end face of the sealing boss 9 to seal the outlet B.

[0030] When the medium is filled into the valve laterally through the inlet A, the medium impacts the first end face of the valve core assembly 3, causing the valve core assembly 3 to receive a force towards the outlet B side. The valve core assembly 3 exerts a force towards the outlet B side on the spring 4, deforming the spring 4, thereby enabling the valve core assembly 3 to move towards the outlet B side and releasing the seal of the outlet B. There is an air hole communicating the inlet A and the outlet B inside the valve core assembly 3. After the outlet of the valve is opened, the medium enters from the inlet A in sequence, passes through the air hole of the valve core assembly 3, and is discharged from the outlet B.

[0031] Given that the force-bearing area of the first end face of the valve core assembly 3 is larger than that of the second end face, and the diameter of the first dynamic seal is larger than that of the second dynamic seal, it can be ensured that the valve core assembly 3 always receives a resultant force towards the outlet B direction during the opening period. During the opening period of the valve core, it is ensured that the resultant force F (F = (D1 2 -D2 2 ) × π / 4 × P) is always greater than the spring force, where D1 is the large inner diameter of the first space (which can also be regarded as the outer diameter of the first end face of the valve core assembly 3), and D2 is the small inner diameter of the first space (which can also be regarded as the outer diameter of the second end face of the valve core assembly 3). After the valve is normally opened, when the medium entering from the inlet A slightly decreases, the valve core assembly 3 still receives a force towards the outlet B, and this force at least partially offsets the force of the spring 4 on the valve core assembly 3, thereby reducing the flutter of the valve core assembly and solving the flutter problem of the valve under small flow and small pressure difference, ensuring the stable performance of the valve after it is opened.

[0032] Among them, the first dynamic seal and the second dynamic seal are spring energy storage sealing rings with different diameters. In this embodiment, it is necessary to determine the diameter difference between the first dynamic seal and the second dynamic seal according to the actual working conditions, the spring, and the friction force of the spring energy storage sealing ring, as long as it is ensured that the resultant force F in the opening direction is much greater than the spring working force P. It can be calculated according to the formula: F × (D1 2 -D2 2 ) × pi / 3.14 / P ≥ 1.5 to determine the diameters of the first dynamic seal and the second dynamic seal.

[0033] The low-temperature anti-flutter check valve of this embodiment is applied to the liquid oxygen or methane pipeline, and the valve can achieve the functions of forward opening and reverse closing under normal temperature, low temperature, low pressure, medium pressure, and high pressure. When the outlet side is under atmospheric pressure, the valve opens when the medium pressure on the inlet side is 1 to 2 MPa. When the outlet side pressure is 8 to 10 MPa, the valve opens when the inlet side pressure is greater than 6 to 8 MPa.

[0034] The anti-flutter check valve of this embodiment can also be applied to scenarios such as multi-engine parallel connection and large-range adjustment of engines. For example, the valve outlet can be divided into two paths and connected to different engines respectively. If one of the engines is shut down and the other path maintains a high pressure of 8 to 10 MPa, the valve cannot open. When the shut-down engine is restarted and the pressure on the inlet side of the valve is greater than 6 to 8 MPa, the valve can open. If an ordinary check valve is used to achieve the functions in the foregoing application scenarios, a cryogenic high-pressure pneumatic control valve needs to be added in front of each check valve, and each pneumatic control valve requires a path of control air. The on-off of the control air requires a solenoid valve, resulting in a huge and complex entire control system. Thus, in application scenarios such as multi-engine parallel connection and large-range adjustment of engines, the anti-flutter check valve of this embodiment can greatly reduce the number of valves and the number of downstream pipelines, reducing the weight and complexity of the rocket system.

[0035] The cryogenic anti-flutter check valve of this embodiment ensures that the valve does not flutter under both large and small flow rates by setting an unbalanced area, solves the flutter problem caused by the large change in the flow rate range of the check valve at low temperature, protects the performance of the product itself, and improves the reliability of the product and the system in a reusable environment.

[0036] In the above embodiment, the transition position between the large-diameter part and the small-diameter part of the first space is set as a stepped transition, and this step is used to limit the movement range of the valve core assembly 3.

[0037] See also Figure 1 and Figure 2 , in one embodiment, the valve core assembly 3 includes a sleeve 31 and a valve core 32. To ensure the sealing performance of the valve port at ultra-low temperature, the non-metal part of the valve core is made of hot-pressed fluoroplastics. The outer wall of the sleeve 31 adapts to the inner diameter change of the first space and is movably arranged in the first space. A first air hole for the medium to pass through is provided inside the sleeve 31. After the valve is opened, the first air hole is communicated with the inlet A and the outlet B. That is to say, the outer wall of the sleeve 31 has a large outer diameter part matching the large-diameter part of the housing 2 and a small outer diameter part matching the small-diameter part of the housing 2.

[0038] A spring installation hole and a valve core installation hole are axially provided on the sleeve 31, and the spring installation hole is arranged on the periphery of the valve core installation hole. One side of the spring 4 is arranged in the spring installation hole, and the other end abuts against the end face of the sealing boss 9 facing the inlet A side. One side of the valve core 32 is arranged in the valve core installation hole of the sleeve 31 and is fixedly connected to the inner wall of the sleeve, and the other end is located at the outlet B and cooperates with the sealing end face (the end face facing the opening B side) of the sealing boss 9.

[0039] Among them, after the spring 4 is compressed by the sealing boss 9, it is installed in the spring installation hole. The spring 4 applies an elastic force to the sleeve 31 and transmits it to the valve core 32, so that the end of the valve core 32 located at the outlet B presses against the sealing end face of the sealing boss 9, thereby realizing the closing of the valve. When the medium is introduced into the valve through the inlet A, the pressure of the medium pushes the sleeve 31 and the valve core 32 to overcome the elastic force of the spring 4, driving the sleeve 31 and the valve core 32 to move simultaneously in the direction of the outlet B, so that the sealing end of the valve core 32 moves away from the sealing end face of the sealing boss 9, realizing the opening of the valve. After the valve is opened, the medium enters the downstream equipment in turn through the inlet A, the first air hole and the outlet B. Since the end face area of the sleeve 31 located in the large inner diameter part of the first space is larger than the end face area located in the small inner diameter part, even if the medium flow rate becomes smaller, the sleeve 31 is still subjected to the pressure towards the outlet B, and this pressure at least partially offsets the elastic force of the spring 4, which can effectively prevent the valve core 32 from fluttering, solves the problem of small flow rate flutter, ensures the stable performance of the product, and at the same time increases the stability of the product itself and the use system.

[0040] Continue to refer to Figure 1 and Figure 2 Furthermore, in order to increase the sealing performance of the valve, a first seal 5 can be provided between the housing 2 and the sleeve 31. A second seal 6 is provided on the end face of the valve core 32 for cooperating with the sealing boss 9. A third seal 7 is provided at the connection between the plug 1 and the housing 2. The first seal 5 includes a first dynamic seal 51 and a second dynamic seal 52, and the second seal 6 and the third seal 7 are static seals.

[0041] The first dynamic seal 51 is a first spring energy storage seal ring provided between the small inner diameter part of the housing 2 and the sleeve 31, and the second dynamic seal 52 is a second spring energy storage seal ring provided between the large inner diameter part of the housing 2 and the sleeve 31. The opening of the first spring energy storage seal ring faces the inlet A side, and the opening of the second spring energy storage seal ring faces the outlet B side. Among them, both the first spring energy storage seal ring and the second spring energy storage seal ring adopt ultra-low temperature metal or non-metal spring energy storage seal rings, realizing dynamic sealing in ultra-low temperature environments, replacing conventional packing seals, reducing friction while improving the sealing performance of the product.

[0042] In addition, a groove for installing the second seal 6 is provided on the end face of the valve core 32 for cooperating with the sealing boss 9, and the second seal 6 is a third seal ring installed in this groove. The plug 1 and the housing 2 are connected by threads, and the connection part is set as a mutually cooperating step. The third seal 7 is a fourth seal ring fixed by being squeezed by the step. The third seal ring and the fourth seal ring can be selected from one of non-metal gaskets, metal gaskets or spring energy storage seal rings.

[0043] Continue to refer to Figure 1 and Figure 2, in the above embodiment, the spool assembly 3 further includes a gland 33 fixedly arranged on the spool 32 near the inlet side. One axial side of the gland 33 presses the first sealing ring (the first dynamic seal 51) tightly between the housing 2 and the sleeve 31, and the other side mates with the plug 1. The end face area of the sleeve 31 on the side mating with the plug 1 is larger than the end face area of the small inner diameter part of the sleeve 31 in the first space. That is to say, the gland 33, the outer wall of the sleeve 31 and the inner wall of the housing 2 cooperate to press the first sealing ring (the first dynamic seal 51) tightly. The gland 33 is provided with a second air hole communicating the inlet A and the first air hole. After the valve is opened, the medium passes through the inlet A, the first air hole, the second air hole and the outlet B in sequence.

[0044] In this embodiment, in the closed state of the valve, a part of the end face of the gland 33 near the inlet A is pressed tightly against the plug 1. When the medium is introduced into the inlet A, the medium acts on one side of the gland 33 near the inlet A, and the medium pressure pushes the gland 33 to drive the sleeve 31 and the spool 32 to move away from the inlet A simultaneously after overcoming the spring force, releasing the seal of the sealing end face of the sealing boss 9 and opening the valve. During the movement, the gland 33 gradually moves away from the plug 1, so that the end face of the gland 33 facing the inlet A is completely in contact with the medium and bears the medium pressure.

[0045] In any of the above embodiments, in order to ensure the smooth passage of the medium, 1-8 air holes can be arranged on the sleeve and the gland in a matching manner.

[0046] Continue to refer to Figure 1 , Figure 2 , in an embodiment, a retaining ring 53 for defining a second sealing ring (the second dynamic seal 52) is provided on the outer wall of the sleeve 31 near the outlet B side. The retaining ring 53, the outer wall of the sleeve 31 and the inner wall of the housing 2 cooperate to press the second sealing ring tightly. The retaining ring 53 is used to prevent the second sealing ring from coming out along the side of the sleeve 31 near the outlet B. In this embodiment, the retaining ring 53 is fixed to the outer wall of the sleeve 31 by threading a steel wire 54 through it, replacing the traditional threaded connection. Compared with the connection method of the thread and the shaft retaining ring structure, the method of fixing the retaining ring with a steel wire in this embodiment has a smaller volume requirement for the retaining ring, reduces the volume of the valve product, and simplifies the installation process.

[0047] Furthermore, in order to improve the service life of the dynamic seal, in this embodiment, at least one annular groove is provided on the outer wall of the sleeve 31 between the first sealing ring (the first dynamic seal 51) and the second sealing ring (the second dynamic seal 52), and a non-metallic support ring is installed in the annular groove. The non-metallic support ring can move along the inner wall of the housing 1. For example, two annular grooves can be provided on the outer wall of the sleeve 31 between the first sealing ring and the second sealing ring. The first annular groove is provided in the small outer diameter part of the sleeve 31, and the second annular groove is provided in the large outer diameter part of the sleeve 31. The first non-metallic support ring 81 is installed in the first annular groove, and the second non-metallic support ring 82 is installed in the second annular groove. With such a setting, the service life of the first sealing ring and the second sealing ring and the stability of the sealing performance can be ensured, and the problem of the seizure of the sealing ring at low temperature is solved.

[0048] In any of the above embodiments, in order to prevent the sealing performance of the chevron seal from decreasing due to pressure buildup caused by medium leakage, an exhaust port C (serial number 12) can be radially opened at the position where the housing 1 transitions from the large inner diameter part to the small inner diameter part, and an exhaust valve is installed on the exhaust port C. When medium leakage occurs at the dynamic seal position, the leaked medium is discharged through the exhaust port C and the exhaust valve. The exhaust valve can prevent the low temperature inside the valve from sucking in air and freezing.

[0049] The above embodiments can be combined with each other and have corresponding technical effects.

[0050] The present invention also provides a liquid oxygen methane engine, which at least includes the low-temperature anti-chatter check valve in any of the above embodiments.

[0051] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A low temperature anti-flutter check valve, characterized in that: At least: Plug cap, housing, valve core assembly and spring; The plugging cover is installed at one end of the shell inlet, and is axially provided with an opening connected to the inside of the shell; the end of the shell away from the plugging cover is the outlet, and the shell is provided with a sealing boss on the inner wall of the side close to the outlet, and a first space is formed between the sealing boss and the plugging cover, and the inner diameter of the first space on the side close to the inlet is larger than the inner diameter on the other side; The valve core assembly is movably arranged in the first space, and an air hole communicating with the inlet and the outlet is arranged inside the valve core assembly; the outer wall of the first side of the valve core assembly has a first outer diameter portion matching with the large inner diameter of the first space and a second outer diameter portion matching with the small inner diameter, and the first outer diameter is larger than the second outer diameter; the end of the second side of the valve core assembly is located at the outlet and matches with the sealing end surface of the sealing boss; A first dynamic seal is provided between the first outer diameter portion of the valve core assembly and the larger inner diameter portion of the housing, and a second dynamic seal is provided between the second outer diameter portion of the valve core assembly and the smaller inner diameter portion of the housing, wherein the diameter of the first dynamic seal is greater than the diameter of the second dynamic seal; One end of the spring is installed on a side of the valve core assembly close to the inlet, and the other end is used to cooperate with the back side of the sealing end surface of the sealing boss to generate a force on the valve core assembly toward the inlet.

2. The low temperature anti-flutter check valve according to claim 1, characterized in that: The valve core assembly comprises a sleeve and a valve core; The outer wall of the sleeve adapts to the change of the inner diameter of the first space and is movably arranged in the first space. The interior of the sleeve is provided with a first air hole for the medium to pass through; after the valve is opened, the first air hole is connected with the inlet and the outlet; The sleeve is axially provided with a spring mounting hole, and the side of the spring away from the sealing boss is arranged in the spring mounting hole; one side of the valve core is arranged in the sleeve and fixedly connected to the inner wall of the sleeve, and the end of the other side is located at the outlet and cooperates with the sealing end face of the sealing boss.

3. The low temperature anti-flutter check valve according to claim 2, characterized in that: The first dynamic seal is a first sealing ring disposed between the large inner diameter portion of the housing and the sleeve, and the second dynamic seal is a second sealing ring disposed between the small inner diameter portion of the housing and the sleeve; The opening of the first sealing ring faces the inlet side, and the opening of the second sealing ring faces the outlet side.

4. The low temperature anti-flutter check valve according to claim 3, characterized in that: The end surface of the valve core used to cooperate with the sealing boss is provided with a second sealing member.

5. The low temperature anti-flutter check valve according to claim 4, characterized in that: The valve core assembly also includes a gland fixedly arranged on the valve core near the inlet side; one axial side of the gland presses the first sealing ring between the housing and the sleeve, and the other side matches the plugging cover; The gland is provided with a second air hole communicating with the inlet and the first air hole.

6. The low temperature anti-flutter check valve according to claim 5, characterized in that: The outer wall of the sleeve close to the outlet side is provided with a retaining ring which limits the second sealing ring; the retaining ring is fixed to the outer wall of the sleeve by a built-in steel wire.

7. The low temperature anti-flutter check valve according to claim 6, characterized in that: At least one annular groove is provided on the outer wall of the sleeve between the first sealing ring and the second sealing ring, and a non-metallic support ring is provided in the annular groove.

8. The low temperature anti-flutter check valve according to any one of claims 2 to 7, characterized in that: An exhaust port is radially arranged at a position where the shell transitions from the large inner diameter portion to the small inner diameter portion.

9. The low temperature anti-flutter check valve according to claim 7, characterized in that: The plugging cover is connected to the shell through threads, and a third sealing member is provided at the connection; the third sealing member is configured as a static seal.

10. A liquid oxygen-methane engine, characterized in that: At least comprising the low temperature anti-flutter one-way valve as described in any one of claims 1 to 9.

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