Self-regulating safety valve

Abstract

The present invention discloses a self-regulating safety valve, which can utilize the flow resistance change under large and small flow rates to form a pressure difference, and use the pressure difference to drive the piston to move, so as to automatically adjust the discharge equivalent diameter under different flow conditions, thereby ensuring that the system pressure is within the required range. When the flow rate is small, the flow resistance of the throttle orifice at the piston is small, and the pressure difference at both ends of the piston is not sufficient to drive the piston to open, and the medium only discharges through the valve orifice on the valve seat through the valve outlet. When the medium flow rate increases, the flow resistance of the throttle orifice at the piston increases, the pressure difference on both sides of the piston increases, and the medium pressure overcomes the second spring force to push the piston to move towards the direction of the valve orifice, thereby opening the relief port. After opening, the discharge equivalent diameter is increased, so that at least part of the medium can be quickly discharged through the relief port.

Description

Technical Field

[0001] The present invention relates to the technical field of liquid rocket engine valve control, and particularly to a self-regulating safety valve. Background Art

[0002] In a liquid rocket engine, high requirements are imposed on the safety valve. Under both large-flow and small-flow working conditions, it is necessary to ensure that the safety valve can be reliably opened and reseated, and the system pressure is maintained within the required range. However, traditional safety valves can only take into account the working condition range of partial flow rates. Beyond this working condition range, the safety valve will no longer be able to work stably.

[0003] Therefore, there is an urgent need to design a self-regulating safety valve that can adapt to the flow discharge requirements under different working conditions. Summary of the Invention

[0004] In view of the above technical problems in the related art, the present invention provides a self-regulating safety valve, which not only improves the adaptability of traditional safety valves, but also can adapt to the flow discharge requirements under different working conditions.

[0005] The present invention provides a self-regulating safety valve, which at least includes a housing, an adjusting unit, a spring seat and a valve seat; one end of the housing is connected to the adjusting unit, and the other end is connected to the valve seat to form a first working chamber. A second working chamber is provided on the side of the valve seat away from the housing; the valve seat is provided with a valve port at one end close to the housing for communicating the first working chamber and the second working chamber, a valve inlet at the other end, and a discharge port for communicating with the valve inlet on the outer wall near the valve inlet; the housing is provided with a valve outlet at a position close to the valve port;

[0006] A first spring and a valve core are provided in the first working chamber; one end of the spring seat is docked with the adjusting unit, and the other end is for setting the first spring. The end of the first spring away from the spring seat is used to press the valve core against the valve port to seal the valve port;

[0007] A second spring and a piston are provided in the second working chamber, and a limiting structure is provided near the valve inlet; one end of the second spring contacts the inner wall of the second working chamber, and the other end presses the piston against the limiting structure; the piston is provided with a flow-limiting hole for communicating the valve port and the valve inlet;

[0008] Adjusting the adjusting unit can adjust the elastic force exerted by the first spring on the valve core;

[0009] When the medium flow rate at the valve inlet is small, the piston is pressed against the limiting structure by the second spring. The outer wall of one end of the piston close to the limiting structure can seal the discharge port, and the valve core can overcome the elastic force of the first spring to release the seal of the valve port, so that the valve port communicates with the valve outlet;

[0010] When the medium flow rate at the valve inlet increases, a pressure difference is formed on both sides of the flow limiting orifice. The medium pressure drives the piston to move in the direction of the second spring against the elastic force of the second spring to release the seal of the discharge port, and the excess medium is discharged through the discharge port.

[0011] In one embodiment, the flow area of the flow limiting orifice is calculated according to parameters such as the inlet pressure of the flow limiting orifice, the outlet pressure of the flow limiting orifice, the flow rate of the flow limiting orifice, and the flow rate of the valve port at the critical state, so as to ensure that at the critical state, the piston can be driven by the medium pressure to release the seal of the discharge port.

[0012] In one embodiment, one end of the piston close to the second spring is provided with a first cavity portion, and the other end is provided with a second cavity portion; the first cavity portion is for the second spring to abut and press, and the second cavity portion communicates with the valve inlet; the outer wall of the piston provided with the second cavity portion is used to seal the discharge port.

[0013] In one embodiment, the second working cavity is provided with a reserved space for the piston to move in its axial direction, and the reserved space can satisfy that the piston fully opens the discharge port.

[0014] In one embodiment, the adjusting unit includes an adjusting stud and a locking nut; the outer wall of the adjusting stud is screwed with the inner wall of the housing; one end of the adjusting stud arranged inside the housing is for installing the spring seat; one end of the adjusting stud extending out of the housing is provided with an adjusting port for adjusting the position of the adjusting stud relative to the housing, and further adjusting the sealing force between the valve core and the valve port; the locking nut is arranged on the housing and screwed with the outer wall of the adjusting stud for locking the adjusting stud on the housing.

[0015] In one embodiment, one end of the spring seat for docking with the adjusting stud is a hemispherical structure, and the other end is a columnar structure; the adjusting stud is provided with an installation groove matching the hemispherical structure; the hemispherical structure is rotatably installed in the installation groove; the first spring is installed around the columnar structure.

[0016] In one embodiment, one end of the valve core close to the first spring is provided with a third cavity portion, and the other end is provided with a sealing tip; the third cavity portion is for the first spring to extend into and press, and the sealing tip is used to extend into the valve port to seal it.

[0017] In one embodiment, a bevel surface is provided at a position where the valve port is used to cooperate with the sealing tip; the bevel surface and the outer wall of the sealing tip form a sealing surface.

[0018] In one embodiment, the limiting structure is a limiting nut provided at the valve port; the limiting nut is screwed to the inner wall of the valve seat.

[0019] In one embodiment, the diameter of the flow limiting hole is smaller than the diameter of the valve port.

[0020] A self - regulating safety valve of the present invention utilizes the flow resistance change under large and small flows to form a pressure difference, and uses the pressure difference to drive the piston to move, so as to automatically adjust the discharge equivalent diameter under different flow conditions, thereby improving the flow adaptability of the safety valve.

[0021] After reading the specific embodiments and viewing the drawings, those skilled in the art will recognize additional features and advantages. Description of the Drawings

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or in the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the following - described drawings 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.

[0023] Figure 1 It is a schematic diagram of the overall structure of the self - regulating safety valve according to the embodiment of the present invention.

[0024] Figure 2 It is the first partial enlarged view of the self - regulating safety valve according to the embodiment of the present invention.

[0025] Figure 3 It is the second partial enlarged view of the self - regulating safety valve according to the embodiment of the present invention. Detailed Embodiments

[0026] The technical solution of the present invention will be further described below in conjunction with the accompanying drawings and through specific embodiments. Spatial relationship terms such as "below", "beneath", "under", "low", "above", "on", "high", etc. are used to facilitate the description and explain the positioning of one element relative to a second element. These terms are intended to cover different orientations of the device, except for 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 each element, region, part, etc., and should not be construed as limiting. Similar terms denote similar elements throughout the description.

[0027] The self-adjusting safety valve provided by the present invention is generally used to maintain the flow rate of the system within a normal range. When the system flow rate exceeds the required range, the pressure at the valve inlet of the safety valve increases, which can then cause the safety valve to open and discharge the increased medium until the system medium flow rate drops back to the normal range, at which point the safety valve closes. However, when the system flow rate exceeds the normal range by too much, the safety valve cannot immediately discharge all of the increased medium, which can easily cause the system pressure to rapidly rise beyond the permitted range. To solve this problem, traditional sealing structures may design the valve orifice to be relatively large. In this case, after the valve core opens the valve orifice, the pressure at the valve orifice drops rapidly, which will not be sufficient to support the valve in the open position, easily causing valve flutter and resulting in unstable operation of the system.

[0028] Therefore, referring to Figure 1 , the present invention provides a self-adjusting safety valve, which at least includes a housing 1, an adjusting unit 2, a spring seat 3, and a valve seat 4. One end of the housing 1 is connected to the spring seat 3, and the other end is connected to the valve seat 4 to form a first working chamber 100. A second working chamber 200 is provided on the side of the valve seat 4 away from the housing 1. The valve seat 4 is provided with a valve orifice 41 at one end close to the housing 1 that can communicate the first working chamber 100 and the second working chamber 200. The other end of the valve seat 4 is provided with a valve inlet 42, and a discharge port 43 for communicating with the valve inlet 42 is provided on the outer wall at a position close to the valve inlet 42. The housing 1 is provided with a valve outlet 11 at a position close to the valve orifice 41 that can communicate with the valve orifice 41.

[0029] A first spring 5 and a valve core 6 are provided in the first working chamber 100. One end of the first spring 5 is installed on the spring seat 3, and the other end is used to press the valve core 6 against the valve orifice 41 on the valve seat, thereby achieving sealing of the valve orifice 41. When a certain flow rate of medium is introduced into the valve inlet 42, when the medium pressure exerted on the valve core 6 at the valve orifice 41 is too high, the medium pressure can overcome the spring force of the first spring 5, causing the valve core 4 to move away from the valve orifice 41, allowing the medium to be discharged through the valve outlet 11. When the medium pressure drops to the required pressure of the system, the valve core 4 returns to its seat to ensure sealing.

[0030] A second spring 7 and a piston 8 are installed within the second working chamber 200, with a limiting structure 9 positioned near the valve inlet 42. One end of the second spring 7 contacts the inner wall of the second working chamber 200, while the other end presses the piston 8 against the limiting structure 9. This limiting structure 9 limits the range of movement of the piston 8 toward the valve inlet 42. When the second spring 7 presses the piston 8 against the limiting structure 9, the outer wall of the piston 8 near the limiting structure 9 seals the drain port 43. The piston 8 also has a flow restriction hole 81 that connects the valve port 41 with the valve inlet 42.

[0031] Specifically, when the medium flow rate at the valve inlet 42 is low (that is, when the elastic force of the first spring 5 is less than the medium pressure and less than the elastic force of the second spring 7), the piston 8 remains compressed against the limiting structure 9, sealing the discharge port 43. At this point, the medium can enter the cavity containing the second spring 7 and the valve port 41 through the flow restriction hole 81. The medium pressure at the valve port 41 overcomes the elastic force of the first spring 5, pushing the valve core 6 toward the first spring 5, creating a gap between the valve core 6 and the valve port 41. The medium flows through the gap between the valve core 6 and the valve port 41 to the valve outlet 11, where it is discharged.

[0032] When the medium flow rate at the valve inlet increases, that is, when the elastic force of the first spring 5 is less than the medium pressure, and the medium pressure is greater than the elastic force of the second spring 7, the flow restriction hole 81 can function as a throttling device. Therefore, a pressure difference is formed between the medium pressure at the valve inlet 42 and the pressure in the cavity where the second spring 7 is located. The medium pressure at the valve inlet drives the piston 8 to overcome the elastic force of the second spring 7 and move toward the second spring 7, thereby releasing the piston 8 from its seal on the discharge port 43, thereby allowing excess medium to be discharged through the discharge port 43.

[0033] When the medium pressure at the valve inlet drops to the pressure required by the system, the valve core 6 returns to its seat under the elastic force of the first spring 5 and seals the valve port 41 .

[0034] The self-regulating safety valve of the embodiment of the present invention utilizes the change in flow resistance under large and small flow rates to form a pressure difference, and utilizes the pressure difference to drive the piston movement, thereby automatically adjusting the discharge equivalent diameter under different flow conditions, thereby improving the flow adaptability of the safety valve.

[0035] In one embodiment, the flow area A1 of the flow restriction hole is determined by the flow restriction hole inlet pressure p1, flow restriction hole outlet pressure p2, flow restriction hole flow rate q under the critical state. m1 and valve port flow q m2 The parameters are calculated as follows:

[0036] pass

[0037] Formula 1: Flow rate formula of flow restriction hole:

[0038] Among them, q m1 is the flow rate through the orifice, kg / s;

[0039] A1 is the orifice area, m2;

[0040] p1 is the inlet pressure of the orifice, MPa;

[0041] R is the gas constant, J / (kg·K);

[0042] T is the inlet temperature of the orifice, K;

[0043] μ1 is the orifice flow coefficient;

[0044] Z1 is a coefficient, dimensionless. When When When When

[0045] Among them, κ is the isentropic exponent;

[0046] p2 is the outlet pressure of the orifice, the inlet pressure of the valve port, MPa;

[0047] Formula 2: Valve port flow formula:

[0048] Among them, q m2 is the valve port flow rate, kg / s;

[0049] A2 is the valve port flow area, m2;

[0050] T2 is the inlet temperature of the valve port, K;

[0051] μ2 is the valve port flow coefficient;

[0052] Z2 is a coefficient, dimensionless. When When

[0053]

[0054] When There is: Among them, p0 is the ambient pressure, MPa.

[0055] Formula 3: The formula for the force on the piston in the critical state is: (p1 - p2)A 活 = F 弹 , among which, A 活 is the outer diameter area of the piston; F 弹 ——The piston spring installation force.

[0056] Among them, in the flow rate balance state, q m1 = q m2 .

[0057] By combining the above formulas, except for the flow area A1 of the flow-limiting orifice which is unknown, other parameters are known or can be calculated. Therefore, according to the required critical pressure and critical flow rate, the flow area A1 of the flow-limiting orifice can be calculated to ensure that the piston can be opened when it exceeds the critical state. After opening, the discharge equivalent diameter is increased, enabling the medium to quickly discharge from the newly added flow path.

[0058] Furthermore, in one embodiment, after repeatedly calculating by combining the formulas during the design process, the diameter range of the flow-limiting orifice is obtained as: 3.4 mm to 3.6 mm.

[0059] In one embodiment, one end of the piston 8 close to the second spring 7 is provided with a first cavity 82, and the other end is provided with a second cavity 83. The first cavity 82 communicates with the second cavity 83 through the flow-limiting orifice 81. The first cavity 82 is for the second spring 7 to abut and press, and at the same time, it can also limit the radial movement of the second spring 7. The second cavity 83 communicates with the valve inlet 42. The outer wall of the piston 8 where the second cavity 83 is provided is used to seal the discharge port 43.

[0060] Furthermore, in order to enable the self-regulating safety valve of the embodiment of the present invention to cover a larger working condition range, a reserved space for the piston 8 to move can be provided axially in the second working cavity 200, and this reserved space can satisfy that the piston 8 fully opens the discharge port 43.

[0061] See also Figure 1 and Figure 3 , the spring seat 3 of the adjusting unit 2 is pressed against the adjusting unit 2 by the first spring 5. By axially moving the adjusting unit 2 along the inner wall of the housing 1, the sealing force between the valve core 6 and the valve port 41 can be adjusted. The self-regulating safety valve of the embodiment of the present invention adjusts the compression amount of the first spring 5 by adjusting the depth of the adjusting unit 2 relative to the housing, so that the elastic force of the first spring 5 is equal to the medium pressure received by the valve core 6 when the safety valve opens.

[0062] Furthermore, the adjusting unit 2 includes an adjusting stud 21 and a locking nut 22. The outer wall of the adjusting stud 21 is screwed to the inner wall of one end of the housing 1 away from the valve seat. One end of the adjusting stud 21 is arranged inside the housing 1, and the other end extends out of the housing 1. The end of the adjusting stud 21 arranged inside the housing 1 is for installing the spring seat 3, and the end of the adjusting stud 21 extending out of the housing 1 is provided with an adjusting port 211 for adjusting the position of the adjusting stud 21 relative to the housing 1, thereby adjusting the sealing force between the valve core and the valve port. The locking nut 22 is arranged on the housing 1 and screwed to the outer wall of the adjusting stud 21 to lock and fix part of the adjusting stud 21 inside the housing 1.

[0063] The self-adjusting safety valve according to the embodiment of the present invention can adjust the compression amount of the first spring by changing the threaded depth of the adjusting stud screwed into the housing, and further can adjust the sealing performance between the valve core and the valve port on the valve seat, so as to realize the opening and closing of the valve port by the valve core under different inlet pressures, and significantly increase the application range of the safety valve.

[0064] Continue to refer to Figure 3 In the above embodiment, one end of the spring seat 3 for docking with the adjusting stud 21 is a hemispherical structure 31, and the other end is a columnar structure 32. An installation groove matching the hemispherical structure 31 is provided at the position where the adjusting stud 21 docks with the spring seat 3.

[0065] Among them, the hemispherical structure 31 is rotatably installed in the installation groove, and the first spring 5 is installed on the periphery of the columnar structure 32. When adjusting the position of the adjusting stud 21 relative to the housing 1, the adjusting stud 21 will perform a spiral movement relative to the housing 1, and the installation groove of the adjusting stud 21 can rotate relative to the hemispherical structure 2, so that relative movement between the columnar structure 32 and the first spring 5 can be avoided, and the generation of foreign matters can be avoided.

[0066] It should be noted that the position where the hemispherical structure 31 is connected to the columnar structure 32 is a cylindrical plate, and the diameter of the cylindrical plate is larger than the diameter of the first spring 5, which is used to limit the displacement of the first spring 5 in the direction towards the hemispherical structure 31.

[0067] At the same time, refer to Figure 1 and Figure 3 In an embodiment, a third cavity 61 is provided at one end of the valve core 6 close to the first spring 5, and a sealing tip 62 is provided at the other end. The first spring 5 extends into the third cavity 61 for pressing, and the outer wall of the third cavity 61 is used to limit the radial position of the first spring 5, ensuring that the first spring 5 can better apply an elastic pressing force to the valve core. Under the action of the elastic pressing force, the sealing tip 62 can extend into the valve port 31 to seal it.

[0068] Further, in order to increase the sealing performance between the valve core 5 and the valve port 31, the end face of the valve port 31 for cooperating with the sealing tip 52 can be set as an inclined surface, so that the inclined surface of the valve port 31 and the outer wall of the sealing tip form a sealing surface, thereby forming a surface seal between the valve core 5 and the valve port 31, and further improving the sealing performance of the valve core to the valve port.

[0069] Refer to Figure 2 In an embodiment, the limiting structure is a limiting nut 81 provided at the valve inlet. The outer wall of the limiting nut 81 is provided with an external thread, and the inner wall of the valve seat 3 close to the valve inlet 32 is provided with an internal thread, and the limiting nut 81 is screwed with the valve seat 3. The inner hole of the limiting nut 81 serves as the valve inlet for the medium to flow through, and the end of the limiting nut 81 close to the second spring 6 is used to limit the position of the piston 7.

[0070] See Figure 1 Figure 1 , in one embodiment, the diameter of the flow-limiting orifice 81 is smaller than that of the valve port 41. The flow-limiting orifice 81 of the piston functions as a throttle. When the valve of the safety valve is opened, the flow-limiting orifice 81 can create a pressure difference between the pressure chamber where the second spring 7 is located and the valve inlet pressure.

[0071] The self-adjusting safety valve according to the embodiment of the present invention can utilize the flow resistance change under different flow rates to form a pressure difference, and use the pressure difference to drive the piston to move, so as to automatically adjust the discharge equivalent diameter under different flow rate conditions, thereby ensuring that the system pressure is within the required range. When the flow rate is small, the flow resistance of the flow-limiting orifice at the piston is small, and the pressure difference across the piston is not sufficient to drive the piston to open. The medium only discharges through the valve port on the valve seat to the valve outlet. When the medium flow rate increases, the flow resistance of the flow-limiting orifice 81 at the piston increases, the pressure difference across the piston 8 increases, and the medium pressure overcomes the spring force of the second spring to push the piston 8 in the direction towards the valve port 41, thereby opening the discharge port 43. After opening, the discharge equivalent diameter is increased, enabling at least part of the medium to be quickly discharged through the discharge port 43.

[0072] The above embodiments of the present invention can be combined with each other and have corresponding technical effects.

[0073] A self-adjusting safety valve of the present invention utilizes the flow resistance change under different flow rates to form a pressure difference, and uses the pressure difference to drive the piston to move, so as to automatically adjust the discharge equivalent diameter under different flow rate conditions, thereby improving the flow rate adaptability of the safety valve.

[0074] The above are only the preferred embodiments of the present invention and are 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 within the protection scope of the present invention.

Claims

1. A self-adjusting safety valve, characterized in that, It includes at least a housing, an adjusting unit, a spring seat and a valve seat; one end of the housing is connected to the adjusting unit, and the other end is connected to the valve seat to form a first working chamber. A second working chamber is provided on the side of the valve seat away from the housing; the valve seat is provided with a valve port at one end close to the housing for communicating the first working chamber and the second working chamber, a valve inlet at the other end, and a discharge port for communicating with the valve inlet on the outer wall near the valve inlet; the housing is provided with a valve outlet at a position close to the valve port. A first spring and a valve core are arranged in the first working chamber; one end of the spring seat is butted against the adjusting unit, and the other end is for arranging the first spring. The end of the first spring away from the spring seat is used to press the valve core against the valve port to seal the valve port. A second spring and a piston are arranged in the second working chamber, and a limiting structure is arranged near the valve inlet; one end of the second spring contacts the inner wall of the second working chamber, and the other end presses the piston against the limiting structure; the piston is provided with a current-limiting hole for communicating the valve port and the valve inlet. Adjusting the adjusting unit can adjust the elastic force exerted by the first spring on the valve core. When the medium flow rate at the valve inlet is small, the piston is pressed against the limiting structure by the second spring. The outer wall of the end of the piston close to the limiting structure can seal the discharge port, and the valve core can overcome the elastic force of the first spring to release the seal of the valve port, so that the valve port is communicated with the valve outlet. When the medium flow rate at the valve inlet increases, a pressure difference is formed on both sides of the current-limiting hole, and the medium pressure drives the piston to move in the direction of the second spring against the elastic force of the second spring to release the seal of the discharge port, and the excess medium is discharged through the discharge port.

2. The self-regulating safety valve according to claim 1, characterized in that, The flow area of the current-limiting hole is calculated according to the inlet pressure of the current-limiting hole, the outlet pressure of the current-limiting hole, the flow rate of the current-limiting hole and the flow rate of the valve port in the critical state, so as to ensure that in the critical state, the piston can be driven by the medium pressure to release the seal of the discharge port.

3. The self-adjusting safety valve according to claim 2, characterized in that, One end of the piston close to the second spring is provided with a first cavity, and the other end is provided with a second cavity; the first cavity is for the second spring to abut and press, and the second cavity is communicated with the valve inlet. The outer wall of the piston provided with the second cavity is used to seal the discharge port.

4. The self-adjusting safety valve according to claim 3, wherein, The second working chamber is provided with a reserved space for the piston to move in its axial direction, and the reserved space can satisfy that the piston fully opens the discharge port.

5. The self-regulating safety valve according to claim 2, characterized in that, The adjusting unit includes an adjusting stud and a locking nut. The outer wall of the adjusting stud is screwed with the inner wall of the housing; one end of the adjusting stud arranged inside the housing is for installing the spring seat; the end of the adjusting stud extending out of the housing is provided with an adjusting port for adjusting the position of the adjusting stud relative to the housing, and further adjusting the sealing force between the valve core and the valve port. The locking nut is arranged on the housing and screwed with the outer wall of the adjusting stud for locking the adjusting stud on the housing.

6. The self-regulating safety valve according to claim 5, characterized in that, One end of the spring seat for docking with the adjusting stud is a hemispherical structure, and the other end is a columnar structure; The adjusting stud is provided with a mounting groove matching the hemispherical structure; the hemispherical structure is rotatably mounted in the mounting groove; The first spring is mounted on the periphery of the columnar structure.

7. The self-regulating safety valve according to any one of claims 1 to 6, characterized in that, One end of the valve core close to the first spring is provided with a third cavity portion, and the other end is provided with a sealing tip; the first spring extends into the third cavity portion for pressing, and the sealing tip is used to extend into the valve port to seal it.

8. The self-regulating safety valve according to claim 7, characterized in that, The valve port is provided with an inclined surface at the position for cooperating with the sealing tip; the inclined surface and the outer wall of the sealing tip form a sealing surface.

9. The self-regulating safety valve according to claim 1, characterized in that, The limiting structure is a limiting nut arranged at the valve port; the limiting nut is screwed to the inner wall of the valve seat.

10. The self-adjusting safety valve according to claim 1, characterized in that, The diameter of the flow limiting hole is smaller than the diameter of the valve port.

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