Novel six-stage depressurization angle type regulating valve

Abstract

The invention discloses a novel six-stage pressure drop angle type regulating valve, and belongs to the technical field of regulating valves. The valve comprises a valve body, a throttling sleeve, a valve seat, a valve clack assembly, a valve deck assembly, a valve rod and a hydraulic actuating mechanism. The throttling sleeve is installed in the valve body assembly. The valve seat is installed in the throttling sleeve, the valve clack assembly is installed in the valve seat, the valve deck assembly is installed on the valve body, one end of the valve rod is connected with a hydraulic actuating mechanism, the other end of the valve rod stretches into the valve deck assembly and then is fixedly connected with the valve clack assembly, and the valve deck assembly is installed on the valve body. And the hydraulic actuating mechanism is mounted on the valve cover assembly. A balanced type six-stage pressure reduction structure is adopted, medium flow is decomposed into a series of small flow sets, kinetic energy in media can be quickly dissipated, the pressure of the media after pressure reduction at each stage is above saturated pressure, the adjusting precision of the valve can be effectively improved, cavitation and flash evaporation are avoided, and the service life of the valve is prolonged. Noise is reduced, and meanwhile vibration of the valve is avoided.

Description

Technical Field

[0001] This invention relates to a six-stage pressure-reducing regulating valve, belonging to the field of regulating valve technology. Background Technology

[0002] The high-pressure water spray regulating valve is installed on the desuperheating water pipeline of the high-pressure bypass system of a supercritical turbine unit to regulate the desuperheating water flow rate of the high-pressure bypass. Supercritical units have extremely high steam parameters, with pressure and temperature far exceeding those of conventional units. The desuperheating water is high-pressure water drawn from the feedwater system, and its pressure is also very high. Because the high-pressure water needs to be reduced to a pressure suitable for the bypass system, the regulating valve faces extremely high inlet pressure and significant pressure differential changes. Therefore, it is a critical component of the high-pressure bypass system, and its performance directly affects the desuperheating function of the high-pressure bypass.

[0003] Currently, high-pressure water spray control valves generally suffer from severe erosion of the internal throttling pairs, especially the sealing surfaces between the valve core and valve seat and the throttling orifice. This results in unsatisfactory pressure reduction, loud valve noise, and severe vibration. Furthermore, the control valves currently used generally employ a multi-stage sleeve orifice throttling pair structure to achieve pressure reduction regulation. However, due to its compact structure, the multi-stage sleeve orifice throttling pair structure has a small pressure reduction range and poor performance, making it difficult to ensure regulation accuracy. In particular, it cannot achieve precise flow regulation under small opening conditions.

[0004] Therefore, it is crucial to solve the bottleneck problem of such regulating valves and propose a new type of pressure-reducing regulating valve suitable for the desuperheating water pipeline of the high-pressure bypass system of supercritical turbines. Summary of the Invention

[0005] This invention proposes a novel six-stage pressure-reducing angle regulating valve, which is suitable for the desuperheating water pipeline of the high-pressure bypass system of supercritical steam turbines.

[0006] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0007] A novel six-stage pressure drop angle regulating valve includes a valve body, a throttling sleeve, a valve seat, a valve disc assembly, a valve cover assembly, a valve stem, and a hydraulic actuator. The throttling sleeve is installed inside the valve body assembly. The valve seat is installed inside the throttling sleeve, the valve disc assembly is installed inside the valve seat, and a valve cover assembly is installed on the valve body. One end of the valve stem is connected to the hydraulic actuator, and the other end extends into the valve cover assembly and is fixedly connected to the valve disc assembly. The valve cover assembly is installed on the valve body, and the hydraulic actuator is installed on the valve cover assembly.

[0008] The lower end of the valve cover assembly is provided with a plurality of uniformly distributed first-stage pressure regulating holes, which are connected to the fluid inlet of the valve body.

[0009] The upper end of the throttling sleeve is provided with several evenly distributed second-stage pressure regulating holes;

[0010] The valve assembly has three levels of pressure regulating holes: a number of evenly distributed third-level pressure regulating holes near the middle of the valve assembly, a number of evenly distributed fourth-level pressure regulating holes near the lower middle part of the valve assembly, and a number of evenly distributed sixth-level pressure regulating holes near the bottom of the valve assembly. The sixth-level pressure regulating holes are connected to the fluid outlet of the valve body.

[0011] The valve seat has several evenly distributed fifth-stage pressure regulating holes at its middle end.

[0012] Furthermore: the valve disc assembly includes a valve disc, a valve disc sleeve, and a valve disc end cap; the valve disc sleeve is welded to the valve disc; the valve disc end cap is welded to the lower end of the valve disc and is located above the sixth-stage pressure regulating hole.

[0013] Furthermore: the valve cover assembly includes a valve cover and a valve cover sleeve, the valve cover sleeve being welded to the valve cover, and the first-stage pressure regulating hole being formed on the valve cover sleeve. The valve cover has a stepped structure and is vertically machined with two symmetrically distributed through holes and two sets of symmetrically distributed threaded holes.

[0014] Furthermore: the valve cover is provided with a packing port, and a packing assembly is provided inside the packing port. The packing assembly includes a first graphite ring and a packing seat ring. The packing seat ring is installed inside the packing port and is coaxially engaged with the valve stem. The first graphite ring is installed inside the packing port and placed on top of the packing seat ring. The first graphite ring is coaxially engaged with the valve stem. The upper end of the packing port is tightly fitted to the lower end of the packing gland.

[0015] Furthermore: a second graphite ring is provided between the valve body and the throttling sleeve, and a spiral wound gasket is provided between the valve body and the valve cover assembly.

[0016] Furthermore: the valve cover assembly is fixedly connected to the valve body by a first bolt, and a first nut is installed above the first bolt, forming a bolt group; the hydraulic actuator is fixedly connected to the valve cover assembly by a second bolt, and a first gasket is installed above the second bolt, and a second nut is installed above the first gasket, forming a bolt group; the packing gland is fixedly connected to the hydraulic actuator by a third bolt, and a second gasket is installed above the third bolt, and a third nut is installed above the second gasket, forming a bolt group.

[0017] Furthermore: the valve body has an angle structure, the inlet and outlet are designed with equal diameter, and the inside has a fluid channel, including a horizontal fluid inlet and a vertical fluid outlet.

[0018] Furthermore: a first-stage pressure regulating chamber S1 exists between the valve cover assembly and the throttling sleeve, and the first-stage pressure regulating hole and the second-stage pressure regulating hole communicate with the first-stage pressure regulating chamber S1; a second-stage pressure regulating chamber S2 exists between the valve disc assembly and the throttling sleeve, and the second-stage pressure regulating hole and the third-stage pressure regulating hole communicate with the second-stage pressure regulating chamber S2; a third-stage pressure regulating chamber S3 is formed between the valve disc and the valve disc end cap in the valve disc assembly, and the third-stage pressure regulating hole and the fourth-stage pressure regulating hole communicate with the third-stage pressure regulating chamber. S3 is connected; a fourth-stage pressure regulating chamber S4 exists between the valve disc assembly and the throttling sleeve, and the fourth-stage pressure regulating hole and the fifth-stage pressure regulating hole are connected to the fourth-stage pressure regulating chamber S4; a fifth-stage pressure regulating chamber S5 exists between the valve disc assembly and the valve seat, and the sixth-stage pressure regulating hole and the fifth-stage pressure regulating hole are connected to the fifth-stage pressure regulating chamber S5; a sixth-stage pressure regulating chamber S6 is formed below the valve disc end cap and at the valve body outlet end in the valve disc assembly, and the sixth-stage pressure regulating hole is connected to the sixth-stage pressure regulating chamber S6.

[0019] The beneficial effects of this invention are as follows:

[0020] 1. Compared with the traditional multi-stage sleeve-type regulating valve, the novel six-stage pressure-reducing angle regulating valve of this invention adopts a balanced six-stage pressure-reducing structure and a six-stage small-orifice throttling structure, which decomposes the medium flow rate into a series of small flow groups, which helps the kinetic energy in the medium to dissipate rapidly. This ensures that the pressure of the medium after each stage of pressure reduction is above the saturation pressure, resulting in a good pressure reduction effect. This effectively improves the regulating accuracy of the valve, avoids cavitation and flashing, reduces noise, and also avoids valve vibration.

[0021] 2. The balanced multi-stage pressure reducing valve disc of the present invention adopts a balanced valve disc that is also a three-stage throttling sleeve and two sealing surfaces. The valve has a high leakage level, and the balanced valve disc structure can reduce the operating force of the actuator.

[0022] 3. Based on the characteristics of high medium flow velocity and easy damage at the throttling pair of the high-pressure water spray regulating valve, the throttling sleeve is made of stainless steel, which has good erosion resistance, wear resistance and abrasion resistance. The medium is sprayed from the periphery of the throttling sleeve to the center, which reduces the kinetic energy of the medium and reduces the erosion and scouring of the valve seat and valve body.

[0023] 4. The valve disc of the present invention adopts a conical sealing surface structure and precipitation-hardening stainless steel material, which has high hardness and erosion resistance, ensuring reliable and durable valve sealing, reducing maintenance costs and power plant shutdowns caused by leakage. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the overall structure of a novel six-stage pressure-reducing angle regulating valve according to the present invention;

[0025] Figure 2This is a schematic diagram of the throttling sleeve structure of the present invention;

[0026] Figure 3 This is a schematic diagram of the valve seat structure of the present invention;

[0027] Figure 4 This is a schematic diagram of the valve disc assembly structure of the present invention;

[0028] Figure 5 This is a schematic diagram of the valve cover assembly structure of the present invention;

[0029] Figure 6 This is a schematic diagram illustrating the six-stage decompression structure and the definition of the decompression cavity of the present invention;

[0030] In the diagram, 1-valve body, 2-throttling sleeve, 201-second-stage pressure regulating hole, 3-valve seat, 301-fifth-stage pressure regulating hole, 4-valve disc assembly, 401-valve disc, 402-valve disc sleeve, 403-valve disc end cap, 411-third-stage pressure regulating hole, 412-fourth-stage pressure regulating hole, 413-sixth-stage pressure regulating hole, 5-first graphite ring, 6-valve cover assembly, 601-valve cover, 602-valve cover sleeve, 61 1-First stage pressure regulating hole, 7-Valve stem, 8-First bolt, 9-First nut, 10-Packing gland, 11-Hydraulic actuator, 12-Second nut, 13-First gasket, 14-Second bolt, 15-Third nut, 16-Second gasket, 17-Third bolt, 18-Packing port, 19-Second graphite ring, 20-Packing seat ring, 21-Spiral spiral washer, 22-Cylindrical pin, 23-Guide ring. Detailed Implementation

[0031] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. After reading the present invention, any modifications of the present invention in various equivalent forms by those skilled in the art will fall within the scope defined by the appended claims.

[0032] Specific implementation method one: Combining Figures 1-6 This embodiment describes a novel six-stage pressure-reducing angle regulating valve, comprising a valve body 1, a throttling sleeve 2, a valve seat 3, a valve disc assembly 4, a valve cover assembly 6, a valve stem 7, a packing gland 10, and a hydraulic actuator 11.

[0033] The throttling sleeve 2 is installed inside the valve body 1; the valve seat 3 is installed inside the throttling sleeve 2, the valve disc assembly 4 is installed inside the valve seat 3, one end of the valve stem 7 is connected to the hydraulic actuator 11, and the other end extends into the valve cover assembly 6 and is connected to the valve disc assembly 4 by a threaded connection. The valve disc assembly 4 and the valve cover 7 are then fixedly connected by a cylindrical pin 22, and a perforation is punched to prevent relative rotation. The valve cover assembly 6 is installed on the valve body 1, and the hydraulic actuator 11 is installed on the valve cover assembly 6.

[0034] The valve disc assembly 4 includes a valve disc 401, a valve disc sleeve 402, and a valve disc end cap 403. The valve disc sleeve 402 is welded to the valve disc 401, and the valve disc end cap 403 is welded to the lower end of the valve disc 401 and the upper end of the sixth-stage pressure regulating hole 413. The upper outer circumference of the valve disc sleeve 402 is provided with three annular grooves, and guide rings 23 are respectively installed in the annular grooves. The guide rings 23 are embedded between the outer wall of the valve disc sleeve 402 and the inner wall of the valve cover sleeve 602, which reduces the gap between the outer wall of the valve disc sleeve 402 and the inner wall of the valve cover sleeve 602, reduces the flow of medium into the inner cavity formed between the valve cover 601 and the valve disc 401, reduces the pressure in the inner cavity, and prevents pressure buildup. The valve disc 401 has two sets of symmetrically distributed through holes 404, which can further reduce the pressure in the inner cavity formed between the valve cover 601 and the valve disc 401, so as to maintain pressure balance between the inner cavity and the first-stage pressure reducing chamber S1. The valve disc 401 adopts a valve wire metal hard seal (the sealing surface is precision machined to form a very narrow contact line. In the closed state, this "line" fits tightly with the valve seat and can withstand extremely high specific pressure). The sealing surface adopts a conical sealing surface structure design, and the material is precipitation hardening stainless steel, which makes the valve disc hard and erosion resistant, ensuring reliable and long-lasting valve sealing.

[0035] The valve cover assembly 6 includes a valve cover 601 and a valve cover sleeve 602, wherein the valve cover sleeve 602 is welded to the valve cover 601.

[0036] In this embodiment, the structural design of the valve cover assembly 6, which includes a valve cover 601 and a valve cover sleeve 602, has the following advantages:

[0037] 1. In the six-stage pressure reduction, the first stage experiences the largest pressure differential, highest flow velocity, and most severe cavitation risk, making it the most damaging part to the materials. The valve cover sleeve 602, a relatively independent and compact component, bears the brunt of the first stage pressure reduction, thus acting as a "sacrificial barrier" or "consumable component." It is the first to withstand the most severe operating conditions, protecting the downstream throttling sleeve 2, valve disc assembly 4, and valve seat 3 from damage. Since the valve cover sleeve 602 is welded to the valve cover 601, it can be repaired and replaced after wear, significantly reducing maintenance costs and complexity.

[0038] 2. The valve cover sleeve 602 extends into the valve body 1, which is equivalent to adding a support structure at the inlet of the valve body 1. It can effectively constrain the flow of fluid in the initial stage of entering the valve cavity, reduce the shaking caused by turbulence, and provide additional support for the entire valve internals (especially the slender valve stem), thereby significantly improving the overall rigidity and vibration resistance of the valve under high pressure differential and high flow rate.

[0039] 3. The valve cover sleeve 602 extending into the valve body 1 can guide and regulate the high-speed fluid in advance, allowing it to enter the subsequent multi-stage pressure reduction areas such as the throttling sleeve and valve disc in a more orderly manner. This helps to reduce unnecessary eddies and impacts, lower overall flow resistance, improve flow characteristics, and further reduce noise.

[0040] The valve cover 601 has a stepped structure and is vertically machined with two symmetrically distributed through holes and two sets of symmetrically distributed threaded holes. A spiral wound washer 21 is installed between the lower end face of the valve cover 601 and the upper end stop of the valve body assembly 1. The top of the valve body 1 is fixedly connected to the valve cover 601 by the first bolt 8. The throttling sleeve 2 and the valve seat 3 are pressed into the valve body 1 by the first graphite ring 5 set between the valve body 1 and the throttling sleeve 2. A first nut 9 is installed above the first bolt 8.

[0041] The packing assembly includes a packing port 18, a second graphite ring 19, and a packing seat ring 20. The packing seat ring 20 is installed inside the valve cover assembly 6 and is coaxially fitted with the valve stem 7. The second graphite ring 19 is installed on the valve cover assembly 6 and is coaxially fitted with the valve stem 7. The upper end of the packing port 18 is tightly fitted to the lower end of the packing gland 10.

[0042] The hydraulic actuator 11 is fixedly connected to the valve cover assembly 6 by a second bolt 17. A first gasket 16 is installed above the second bolt 17, and a second nut 15 is installed above the first gasket 16. The packing gland 10 is fixedly connected to the hydraulic actuator 11 by a third bolt 14. A second gasket 13 is installed above the bolt, and a third nut 14 is installed above the second gasket 13.

[0043] The valve body 1 has an angle structure with equal diameter inlet and outlet, and internal fluid channels including a horizontal fluid inlet and a vertical fluid outlet. The lower end of the valve cover assembly 6 has several evenly distributed first-stage pressure regulating holes 611, which are connected to the horizontal fluid inlet. The upper end of the throttling sleeve 2 has several evenly distributed second-stage pressure regulating holes 201. The valve disc assembly 4 has three-stage pressure regulating holes: several evenly distributed third-stage pressure regulating holes 411 near the middle of the valve disc assembly 4, several evenly distributed fourth-stage pressure regulating holes 412 near the lower middle part of the valve disc assembly 4, and several evenly distributed sixth-stage pressure regulating holes 413 near the bottom of the valve disc assembly 4. The sixth-stage pressure regulating holes 413 are connected to the vertical fluid outlet. The middle end of the valve seat 3 has several evenly distributed fifth-stage pressure regulating holes 301.

[0044] A first-stage pressure regulating chamber S1 exists between the valve cover assembly 6 and the throttling sleeve 2, and the first-stage pressure regulating hole 611 and the second-stage pressure regulating hole 201 are connected to the first-stage pressure regulating chamber S1; a second-stage pressure regulating chamber S2 exists between the valve disc assembly 4 and the throttling sleeve 2, and the second-stage pressure regulating hole 201 and the third-stage pressure regulating hole 411 are connected to the second-stage pressure regulating chamber S2; a third-stage pressure regulating chamber S3 is formed between the valve disc 401 and the valve disc end cap 403 in the valve disc assembly 4, and the third-stage pressure regulating hole 411 and the fourth-stage pressure regulating hole 412 are connected to the third-stage pressure regulating chamber. S3 is connected; there is also a fourth-stage pressure regulating chamber S4 between the valve disc assembly 4 and the throttling sleeve 2, and the fourth-stage pressure regulating hole 412 and the fifth-stage pressure regulating hole 301 are connected to the fourth-stage pressure regulating chamber S4; there is also a fifth-stage pressure regulating chamber S5 between the valve disc assembly 4 and the valve seat 3, and the sixth-stage pressure regulating hole 413 and the fifth-stage pressure regulating hole 301 are connected to the fifth-stage pressure regulating chamber S5; the valve disc end cap 403 in the valve disc assembly 4 forms a sixth-stage pressure regulating chamber S6 with the outlet end of the valve body assembly 1 below, and the sixth-stage pressure regulating hole 413 is connected to the sixth-stage pressure regulating chamber S6.

[0045] Control Principle: The pressure and flow rate of the medium are controlled by the valve stem 7, which connects to the valve disc assembly 6, moving up and down within the valve seat 3. This changes the flow area of ​​the medium through the valve disc, thus regulating the medium pressure. Control signals from the DCS are transmitted to the hydraulic actuator 11, driving the valve stem 7 and valve disc assembly 6 to move, thereby changing the valve opening. When the valve stem 7 moves upward, the flow area increases; when the valve stem 7 moves downward, the flow area decreases. After passing through each stage of orifice throttling, the medium converges and sprays from the periphery towards the center. After six stages of throttling and pressure reduction, it flows out from the valve outlet.

[0046] The six-stage pressure-reducing angle regulating valve in this embodiment differs from conventional designs. Instead of using the conventional method of stacking multiple "sleeves" to achieve pressure reduction regulation, the six-stage pressure-reducing structure is respectively set on four key components: valve cover assembly 6, throttling sleeve 2, valve disc assembly 4, and valve seat 3. This forms a new, multi-level pressure release path. Through the innovative spatial structural layout of the various components within the valve, the valve can achieve more flexible and precise flow and pressure regulation.

[0047] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A new type of six-stage pressure drop angle regulating valve, characterized in that, It includes valve body (1), throttle sleeve (2), valve seat (3), valve clapper assembly (4), valve cover assembly (6), valve stem (7) and hydraulic actuator (11), the throttle sleeve (2) is installed in valve body assembly (1), the valve seat (3) is installed in the throttle sleeve (2), the valve clapper assembly (4) is installed in the valve seat (3), the valve body (1) is installed with valve cover assembly (6), the valve stem (7) one end is connected with hydraulic actuator (11), the other end is inserted into valve cover assembly (6) back, with the valve clapper assembly (4) fixed connection, the valve cover assembly (6) is installed on the valve body (1), the hydraulic actuator (11) is installed on the valve cover assembly (6), The lower end of the valve cover assembly (6) is provided with a plurality of uniformly distributed first-stage pressure regulating holes (611), and the first-stage pressure regulating holes (611) are communicated with the fluid inlet of the valve body (1). The upper end of the throttle sleeve (2) is provided with a plurality of uniformly distributed second-stage pressure regulating holes (201). The valve clapper assembly (4) is provided with three-stage pressure regulating holes, which are a plurality of uniformly distributed third-stage pressure regulating holes (411) near the middle of the valve clapper assembly (4), a plurality of uniformly distributed fourth-stage pressure regulating holes (412) near the lower middle of the valve clapper assembly (4), and a plurality of uniformly distributed sixth-stage pressure regulating holes (413) near the bottom of the valve clapper assembly (4), and the sixth-stage pressure regulating holes (413) are communicated with the fluid outlet of the valve body (1). The middle end of the valve seat (3) is provided with a plurality of uniformly distributed fifth-stage pressure regulating holes (301).

2. A new type of six-stage pressure reducing angle valve according to claim 1, characterized in that: The valve clapper assembly (4) includes a valve clapper (401), a valve clapper sleeve (402) and a valve clapper end cover (403), the valve clapper sleeve (402) is welded to the valve clapper (401), and the valve clapper end cover (403) is welded to the lower end of the valve clapper (401) and located at the upper end of the sixth-stage pressure regulating holes (413).

3. A new type of six-stage pressure reducing angle valve according to claim 1, characterized in that: The valve cover assembly (6) includes a valve cover (601) and a valve cover sleeve (602), the valve cover sleeve (602) is welded to the valve cover (601), and the first-stage pressure regulating holes (611) are formed in the valve cover sleeve (602).

4. A new type of six-stage pressure reducing angle valve according to claim 3, characterized in that: The valve cover (601) is provided with a packing port (18), the packing port (18) is provided with a packing assembly, the packing assembly includes a first graphite ring (19) and a packing seat ring (20), the packing seat ring (20) is installed in the packing port (18) and coaxially matched with the valve stem (7), the first graphite ring (19) is installed in the packing port (18) and located above the packing seat ring (20), and the first graphite ring (19) is coaxially matched with the valve stem (7), and the upper end of the packing port (18) is tightly attached to the lower end of the packing gland (10).

5. A new type of six-stage pressure reducing angle valve according to claim 1, characterized in that: A second graphite ring (5) is arranged between the valve body (1) and the throttle sleeve (2), and a winding gasket (21) is arranged between the valve body (1) and the valve cover assembly (6).

6. A new type of six-stage pressure reducing angle valve according to claim 1, characterized in that: The valve cover assembly (6) is fixedly connected with the valve body (1) through a first bolt (8), a first nut (9) is installed above the first bolt (8), and the first bolt (8) and the first nut (9) form a bolt set; the hydraulic actuator (11) is fixedly connected with the valve cover assembly (6) through a second bolt (17), a first gasket (16) is installed above the second bolt (17), a second nut (15) is installed above the first gasket (16), and the second bolt (17), the first gasket (16) and the second nut (15) form a bolt set; the packing gland (10) is fixedly connected with the hydraulic actuator (11) through a third bolt (14), a second gasket (13) is installed above the third bolt (14), a third nut (14) is installed above the second gasket (13), and the third bolt (12), the second gasket (13) and the third nut (14) form a bolt set.

7. A new type of six-stage pressure reducing angle valve according to claim 1, characterized in that: The valve body (1) is an angular structure, the inlet and outlet are designed with equal diameters, and the inside has a fluid passage, including a horizontal fluid inlet and a vertical fluid outlet.

8. A new type of six-stage pressure reducing angle valve according to claim 1, characterized in that: The valve cover assembly (6) and the throttle sleeve (2) have a first-stage pressure regulating cavity S1, the first-stage pressure regulating hole (611) and the second-stage pressure regulating hole (201) are in communication with the first-stage pressure regulating cavity S1; the valve disc assembly (4) and the throttle sleeve (2) have a second-stage pressure regulating cavity S2, the second-stage pressure regulating hole (201) and the third-stage pressure regulating hole (411) are in communication with the second-stage pressure regulating cavity S2; the valve disc (401) and the valve disc end cover (403) in the valve disc assembly (4) form a third-stage pressure regulating cavity S3, the third-stage pressure regulating hole (411) and the fourth-stage pressure regulating hole (412) are in communication with the third-stage pressure regulating cavity S3; the valve disc assembly (4) and the throttle sleeve (2) further have a fourth-stage pressure regulating cavity S4, the fourth-stage pressure regulating hole (412) and the fifth-stage pressure regulating hole (301) are in communication with the fourth-stage pressure regulating cavity S4; the valve disc assembly (4) and the valve seat (3) further have a fifth-stage pressure regulating cavity S5, the sixth-stage pressure regulating hole (413) and the fifth-stage pressure regulating hole (301) are in communication with the fifth-stage pressure regulating cavity S5; the valve disc end cover (403) below the valve disc assembly (4) and the outlet end of the valve body (1) form a sixth-stage pressure regulating cavity S6, and the sixth-stage pressure regulating hole (413) is in communication with the sixth-stage pressure regulating cavity S6.

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