Small volume large flow safety valve

Abstract

The application discloses a small-volume large-flow safety valve, which comprises a valve body, a main valve core, a spring, an adjusting seat and a sealing gasket; the lower end gas inlet hole of the valve body comprises a contraction section and a throat portion, and a ring-shaped flow guide surface is arranged to form a Laval tube rotary spline profile; the ring-shaped flow guide surface is gradually expanded along the medium flow direction; after the medium is accelerated through the profile, the medium is branched to each annular gas outlet hole, large-flow pressure relief is realized, and airflow congestion is eliminated; the valve body is provided with annular gas outlet holes and back pressure balance holes to form a main pressure relief channel and a back pressure balance double-channel flow channel; a clasp spring is arranged in the valve body to limit the maximum opening stroke of the main valve core; the half angle of the fluid transition section of the main valve core is not less than 45 DEG, and an anodized anti-erosion coating is arranged on the medium contact surface; the application has the advantages of compact structure, small volume, adaptation to complex working conditions of high-pressure gas supply of large spacecraft, stable flow field, anti-erosion, reliable sealing, convenient assembly and pressure regulation operation.

Description

Technical Field

[0001] This invention relates to a small-volume, high-flow safety valve. Background Technology

[0002] Safety valves are a common type of valve product widely used in the aerospace field, primarily ensuring the safe and stable operation of gas systems. Large spacecraft, constrained by cabin space, typically store internal gaseous media using high-pressure compression, with some media exhibiting extremely high compression. While this method saves internal space, it significantly increases the flow requirements of the piping system, sometimes even resulting in supersonic flow. In the high-pressure throttling structure of large spacecraft accumulators, safety valves must be capable of handling the system's maximum flow rate; therefore, flow rate is a core design parameter for safety valves. Simultaneously, spacecraft equipment faces stringent weight and size limitations, requiring aerospace safety valves to simultaneously meet the contradictory design requirements of high flow rate and small size.

[0003] Market research indicates that the design focus of conventional safety valves is solely on their opening and closing pressure specifications. This is because as long as the valve can open smoothly, it meets the flow requirements of simple pneumatic systems, eliminating the need for additional flow performance optimization. Conventional small safety valves suffer from drawbacks such as poor opening and closing pressure sensitivity, limited flow rate, and insufficient permissible number of actuations. For example, Chinese utility model patent CN222577420U discloses a simple safety valve. This product consists of a valve body, a rotary valve core, and an L-shaped outlet pipe. It only has a single flow channel for outlet and lacks a Laval profile composed of an inlet contraction-throat and an annular expansion guide surface, as well as an independent back pressure balance channel. It is prone to blockage when high-pressure media flows, and its leakage capacity is insufficient, making it unsuitable for the high-flow conditions of aerospace. On the other hand, existing high-flow safety valves are generally too large. Chinese utility model patent CN222316056U discloses a high-pressure, high-flow composite sealed safety valve, which relies on increasing the pressure-bearing area of ​​the valve to improve flow, resulting in a significant increase in the overall size. The valve only has a single pressure relief channel and lacks a dual-channel structure composed of an annular outlet and a back pressure balance hole. It also lacks a segmented Laval acceleration profile, making it prone to generating shock waves and large pressure fluctuations in high-pressure airflow, making it difficult to achieve both miniaturization and stable supersonic pressure relief.

[0004] In summary, there is currently no safety valve product in the existing technology that can simultaneously meet the needs of large spacecraft and take into account both small size and high flow rate performance. Therefore, there is an urgent engineering need to develop a space-specific safety valve that is compact, reliable, small in size, and has a high flow rate. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a small-volume, high-flow safety valve. This valve meets the requirements for safe pressure relief in high-pressure pipelines of large spacecraft, and features a compact structure, strong flow relief capacity, stable flow field, and long service life.

[0006] To achieve the above objectives, the present invention employs the following technical solutions: A small-volume, high-flow safety valve includes a valve body (1), a main valve core (2), a spring (5), an adjusting seat (6), and a sealing gasket (9). The valve body (1) has a cavity (15) inside, and the main valve core (2) is slidably installed in the cavity (15) along the axial direction of the valve body (1); The lower end of the valve body (1) is provided with an air inlet (11) that connects to the cavity (15). The air inlet (11) includes a constriction section and a throat. An annular guide surface (14) is provided at the connection between the air inlet (11) and the cavity (15). The annular guide surface (14) is an expansion section. The air inlet (11) and the annular guide surface (14) together form a Laval tube rotary spline profile. The side wall of the valve body (1) is provided with several annular air outlets (12) and back pressure balance holes (13) that connect to the cavity (15). Along the direction of medium flow, the air inlet (11) and the annular guide surface (14) combine to form a complete Laval tube rotary spline profile. After the medium is accelerated by this profile, it is diverted to each annular air outlet (12), thereby achieving large flow pressure relief and eliminating airflow blockage. The sealing gasket (9) is fixedly installed in the groove of the main valve core (2), and the sealing gasket (9) can seal and fit with the valve seat of the valve body (1) under the pre-tightening force of the spring (5); The adjusting seat (6) is threaded onto the inner wall of the upper end of the valve body (1), and the spring (5) is abutted between the adjusting seat (6) and the main valve core (2). Rotating the adjusting seat can adjust the spring preload. When the medium pressure overcomes the spring preload and pushes the main valve core (2) away from the valve seat, a pressure relief gap is formed between the sealing gasket (9) and the valve seat; the circumferential vent (12) is connected to the pressure relief gap to form the main pressure relief channel, and the back pressure balance hole (13) is connected to the fitting gap between the outer wall of the main valve core (2) and the inner wall of the cavity (15) to form the back pressure balance channel.

[0007] Furthermore, the spring (5) is fitted with a first spring seat (3) and a second spring seat (4) at both ends respectively. The ball head of the first spring seat (3) abuts against the V-groove of the main valve core (2), and the ball head of the second spring seat (4) abuts against the V-groove of the adjusting seat (6), ensuring that the spring is subjected to stable force without deviation.

[0008] Furthermore, the upper outer wall of the valve body (1) is threadedly connected to the pressure cap (7) and the locking nut (8). The pressure cap (7) abuts against the adjusting seat (6) and cooperates with the locking nut to achieve axial limiting.

[0009] Furthermore, a retaining ring (10) is provided in the groove on the inner wall of the valve body (1). The retaining ring (10) is located on the opening movement path of the main valve core, limiting the maximum opening stroke of the main valve core (2).

[0010] Furthermore, the number of circumferential air outlets (12) is even, and they are evenly arranged around the valve body to balance the airflow impact force.

[0011] Furthermore, the back pressure balance hole (13) is located on the side of the valve body (1) away from the air inlet, and is connected to the valve body (1) and the main valve core (2) through the fitting gap to form a back pressure balance channel.

[0012] Furthermore, the fluid transition section of the main valve core (2) near the air inlet has a half angle of not less than 45°, and the medium contact surface of the main valve core (2) is provided with an anodized anti-erosion coating.

[0013] The present invention has the following advantages: I. The present invention has a high degree of integration of components and a compact structure, which can meet the installation requirements of spacecraft in a confined space. At the same time, it relies on the Laval annular guide surface and multi-channel exhaust structure to achieve high flow rate pressure relief, thus resolving the contradiction between miniaturization and high flow rate. 2. Set a back pressure balance hole to stabilize the outlet pressure of the flow channel, eliminate the problems of supersonic airflow blockage and shock wave under high pressure conditions, and protect the valve body and main valve core; 3. The dual structure of spring seat ball head positioning and snap ring stroke limit effectively suppresses the working chatter of the main valve core and reduces the impact wear of the sealing surface; IV. The anodized protective coating on the main valve core, combined with a large-angle transition cone surface, enhances the erosion resistance of the main valve core and extends the service life of the valve. 5. The opening pressure can be easily adjusted by adjusting the seat. After the gland and locking nut are locked, the parameters are stable, and the assembly and debugging operations are simple. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the overall structure of a small-volume, high-flow safety valve.

[0015] Figure 2 This is a cross-sectional view of a small-volume, high-flow safety valve.

[0016] Figure 3 This is an exploded view of a small-volume, high-flow safety valve.

[0017] Figure 4 This is a cross-sectional view of the valve body of a small-volume, high-flow safety valve.

[0018] Figure 5 This is a cross-sectional view of the main valve core of a small-volume, high-flow safety valve.

[0019] In the diagram: 1 - valve body, 2 - main valve core, 3 - first spring seat, 4 - second spring seat, 5 - spring, 6 - adjusting seat, 7 - pressure cap, 8 - locking nut, 9 - sealing gasket, 10 - snap ring, 11 - air inlet, 12 - circumferential air outlet, 13 - back pressure balance hole, 14 - annular guide surface, 15 - cavity. Detailed Implementation

[0020] The present invention will now be described in detail with reference to the accompanying drawings.

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0022] Example 1: like Figure 1 - Figure 5 As shown, a small-volume, high-flow safety valve comprises a valve body 1, a main valve core 2, a spring 5, an adjusting seat 6, and a sealing gasket 9. The valve body 1 has an internal cavity 15, and the main valve core 2 can slide axially along the cavity 15. An air inlet 11 is opened at the lower end of the valve body 1, connecting to the cavity 15. An annular guide surface 14 is provided above the air inlet 11. The annular guide surface 14 gradually expands from the air inlet 11 towards the cavity 15 along the direction of medium flow, forming an expansion section. Combined with the contraction section and throat of the air inlet 11, it forms a Laval tube rotational spline profile. After the medium is accelerated by this profile, it is diverted to various circumferential air outlets 12, thereby achieving high-flow-rate pressure relief and eliminating airflow congestion. Multiple sets of circumferential air outlets 12 and back pressure balance holes 13 are arranged on the side wall of the valve body.

[0023] The sealing gasket 9 is fixed in the sealing groove at the bottom of the main valve core 2 by a rolling process. Before the sealing gasket is rolled, a small vent hole is opened at the bottom of the sealing groove of the main valve core to prevent air from affecting the stability of the installation of the sealing gasket 9. The sealing gasket and the sealing groove adopt an interference fit. Before rolling, the coaxiality of the two is ensured to improve the sealing fit effect. After assembly, the sealing gasket 9 can fit tightly with the valve body and valve seat to achieve a seal. The sealing chamfer of the valve body and valve seat is machined with CNC tool tip arc compensation to ensure no burrs. The surface roughness of the sealing surface is controlled to Ra0.4, which improves the fitting accuracy and sealing performance of the sealing pair.

[0024] Adjusting seat 6 is screwed onto the inner wall of the upper end of valve body 1. Spring 5 is arranged between adjusting seat 6 and main valve core 2. A first spring seat 3 and a second spring seat 4 are respectively fitted onto the two ends of the spring. The ball head of the first spring seat 3 engages with the V-groove of the main valve core, and the ball head of the second spring seat 4 fits against the V-groove of the adjusting seat to prevent the spring from tilting under pressure. A pressure cap 7 and a locking nut 8 are sequentially installed on the outer wall of the upper end of the valve body. The pressure cap fits against the adjusting seat to achieve axial limiting, and the locking nut presses the pressure cap to lock the position of the adjusting seat. A retaining groove is provided on the inner wall of the valve body cavity, and a retaining spring 10 engages with the retaining groove to limit the maximum upward stroke of the main valve core.

[0025] The annular guide surface 14 and the air inlet 11 adopt a Laval tube rotary spline structure to adapt to the supersonic flow of high-pressure media; the number of circumferential air outlets 12 is set to an even number and evenly distributed along the circumference of the valve body to balance the circumferential impact force generated by the venting airflow. The half-angle of the fluid transition section of the main valve core is set to 45° or more, and the medium scouring contact surface is treated with an anodized anti-erosion coating to prevent the supersonic airflow from eroding the main valve core and generating excess material.

[0026] Normal sealing condition: When the pipeline pressure is lower than the valve opening pressure, the preload of spring 5 pushes the main valve core 2 downward, the sealing gasket 9 presses the valve body 1 valve seat, and the high-pressure medium flowing in through the air inlet 11 is sealed in the cavity 15, with no external leakage.

[0027] Overpressure relief condition: The pipeline pressure rises to overcome the preload of spring 5, and the medium pushes the main valve core 2 to rise, and the sealing gasket 9 separates from the valve seat to form a pressure relief gap; the fluid medium is divided into two paths. The main fluid is accelerated along the annular guide surface 14 and discharged at high speed from the annular outlet 12, which can form a stable supersonic flow under high pressure; a small amount of fluid flows into the downstream area through the back pressure balance hole 13 to stabilize the outlet back pressure, maintain the throat pressure ratio, and eliminate airflow obstruction; during this process, the retaining spring 10 limits the maximum opening of the main valve core to avoid large-scale jumping and chattering of the main valve core.

[0028] Pressure reset stage: The pipeline medium pressure drops, spring 5 pushes the main valve core 2 downward to reset, the sealing gasket 9 re-fits the valve seat, the pressure relief channel is closed, and the sealing state is restored.

[0029] This invention is not limited to the specific embodiments described above. The invention extends to any new feature or combination disclosed in this specification, as well as any new method or process step or combination disclosed herein.

Claims

1. A small-volume, high-flow-rate safety valve, characterized in that: Includes valve body (1), main valve core (2), spring (5), adjusting seat (6) and sealing gasket (9); The valve body (1) has a cavity (15) inside, and the main valve core (2) is slidably installed in the cavity (15) along the axial direction of the valve body (1); The lower end of the valve body (1) is provided with an air inlet (11) that connects to the cavity (15). The air inlet (11) includes a constriction section and a throat. An annular guide surface (14) is provided at the connection between the air inlet (11) and the cavity (15). The annular guide surface (14) is an expansion section. The air inlet (11) and the annular guide surface (14) together form a Laval tube rotary spline profile. The side wall of the valve body (1) is provided with several annular air outlets (12) and back pressure balance holes (13) that connect to the cavity (15). Along the direction of medium flow, the air inlet (11) and the annular guide surface (14) combine to form a complete Laval tube rotary spline profile. After the medium is accelerated by this profile, it is diverted to each annular air outlet (12), thereby achieving large flow pressure relief and eliminating airflow blockage. The sealing gasket (9) is fixedly installed in the groove of the main valve core (2), and the sealing gasket (9) can seal and fit with the valve seat of the valve body (1) under the pre-tightening force of the spring (5); The adjusting seat (6) is threaded onto the inner wall of the upper end of the valve body (1), and the spring (5) is abutted between the adjusting seat (6) and the main valve core (2). Rotating the adjusting seat can adjust the spring preload. When the medium pressure overcomes the spring preload and pushes the main valve core (2) away from the valve seat, a pressure relief gap is formed between the sealing gasket (9) and the valve seat; the circumferential vent (12) is connected to the pressure relief gap to form the main pressure relief channel, and the back pressure balance hole (13) is connected to the fitting gap between the outer wall of the main valve core (2) and the inner wall of the cavity (15) to form the back pressure balance channel.

2. The small-volume, high-flow safety valve according to claim 1, characterized in that: The spring (5) is fitted with a first spring seat (3) and a second spring seat (4) at both ends. The ball head of the first spring seat (3) abuts against the V-groove of the main valve core (2), and the ball head of the second spring seat (4) abuts against the V-groove of the adjusting seat (6), ensuring that the spring is under stable force without deviation.

3. The small-volume, high-flow safety valve according to claim 1, characterized in that: The valve body (1) has a threaded connection between the pressure cap (7) and the locking nut (8) on the upper outer wall. The pressure cap (7) abuts against the adjusting seat (6) and works with the locking nut to achieve axial positioning.

4. The small-volume, high-flow safety valve according to claim 1, characterized in that: A retaining ring (10) is installed in the groove on the inner wall of the valve body (1). The retaining ring (10) is located on the opening movement path of the main valve core, limiting the maximum opening stroke of the main valve core (2).

5. The small-volume, high-flow safety valve according to claim 1, characterized in that: The number of circumferential air outlets (12) is even, and they are evenly arranged along the circumference of the valve body to balance the impact force of the airflow.

6. The small-volume, high-flow safety valve according to claim 1, characterized in that: The back pressure balance hole (13) is located on the side of the valve body (1) away from the air inlet, and is connected through the fitting gap between the valve body (1) and the main valve core (2).

7. The small-volume, high-flow safety valve according to claim 1, characterized in that: The fluid transition section of the main valve core (2) near the air inlet has a half angle of not less than 45°, and the medium contact surface of the main valve core (2) is provided with an anodized anti-erosion coating.

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