Multi-stage pressure and noise reduction regulating valve

Abstract

The invention relates to the technical field of fluid control and management, in particular to a multi-stage pressure and noise reduction regulating valve which is characterized in that a fluid channel is arranged in a valve body and comprises a fluid outlet and a fluid inlet; the valve seat comprises a multi-layer valve cylinder and a first opening, a first throttling hole is formed in the multi-layer valve cylinder, and the first throttling hole communicates with the fluid inlet; the valve cage is fixedly connected with the valve seat and comprises a multi-layer valve wall and a first through hole, one end of the first through hole is connected with the first open hole, and the multi-layer valve wall is provided with a second throttling hole communicated with the fluid outlet; the valve cover is fixedly connected with the valve body; the valve plug is slidably arranged in the cavity; the valve rod is fixedly connected with the valve plug and arranged in the second through hole in a sliding mode. The valve cylinders and the valve walls are each provided with three layers, the first throttling holes in every two adjacent valve cylinders are arranged in a staggered mode, and the second throttling holes in every two adjacent valve cages are arranged in a staggered mode. Through the multiple layers of valve cylinders and the staggered throttling holes in the valve wall, the frequency of bubble formation and collapse is reduced, and fluid noise and the erosion risk of equipment are reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of fluid control and management, and in particular to a multi-stage pressure-reducing and noise-reducing regulating valve. Background Art

[0002] As a core actuator in industrial automation process control, a control valve's primary function is to precisely adjust process parameters such as flow, pressure, temperature, and liquid level in a pipeline by varying the valve opening. Its operating principle typically involves forming a variable throttling channel between the valve core and the valve seat.

[0003] When a fluid flows through the throttling surface formed by the valve core and seat of a control valve, its flow rate increases dramatically while its static pressure drops abruptly. When the pressure downstream of the throttling surface drops to or below the saturated vapor pressure of the fluid at that temperature, boiling occurs within the fluid, forming a large number of bubbles. These bubbles burst within a very short time as they flow with the fluid to the downstream pressure recovery zone. This instantaneous collapse generates extremely high localized impact forces, which not only severely erode and damage the valve core, cage, seat, and internal surfaces of the valve body, significantly shortening the valve's service life, but also generate intense fluid dynamic noise during the bubble generation, flow, and collapse process itself, significantly increasing noise levels.

[0004] Therefore, there is an urgent need for a regulating valve with an improved structure, which can reduce the noise of fluid flowing through the regulating valve through the improved structure. Summary of the Invention

[0005] In view of at least one of the above technical problems, the present invention provides a multi-stage pressure-reducing and noise-reducing regulating valve, which uses structural improvements to reduce the noise of fluid flowing through the regulating valve.

[0006] According to a first aspect of the present invention, there is provided a multi-stage pressure reduction and noise reduction regulating valve, comprising: A valve body having a fluid passage therein, including a fluid outlet and a fluid inlet; a valve seat, disposed inside the valve body, comprising a multi-layer valve cylinder and a first opening disposed at one end of the valve cylinder, wherein each of the multi-layer valve cylinders is provided with a first throttle hole, the first throttle hole being in communication with the fluid inlet; a valve cage disposed inside the valve body and fixedly connected to the valve seat, comprising a multi-layer valve wall, wherein the valve wall has a first through hole at its center, one end of the first through hole is connected to the first opening, and each of the multi-layer valve wall has a second throttling hole, the second throttling hole being connected to the fluid outlet; a valve cover fixedly connected to the valve body, wherein the valve body has a second through hole at its center, the second through hole being divided into a large diameter section and a small diameter section, the large diameter section being connected to the first through hole, and the large diameter section and the first through hole forming a chamber; A valve plug is slidably disposed in the chamber and can be relatively moved closer to or farther away from the valve cover; a valve stem fixedly connected to the valve plug, slidably disposed in the second through hole, and capable of relatively approaching or moving away from the valve seat; Wherein, the valve cylinder and the valve wall both have three layers, the first throttling holes on two adjacent valve cylinders are staggered, and the second throttling holes on two adjacent valve cages are staggered; the fluid flows in through the inlet, flows through the first throttling hole to the first opening, passes through the first opening to the first through hole, and flows through the second throttling hole to the outlet.

[0007] In some embodiments of the present invention, the first throttle holes and the second throttle holes are both circular in shape, and the first throttle holes or the second throttle holes in the same layer are evenly arranged horizontally and vertically.

[0008] In some embodiments of the present invention, the innermost diameter of the valve wall is smaller than the innermost diameter of the valve cylinder, and when the valve plug approaches the valve seat, the valve plug abuts against the valve seat.

[0009] In some embodiments of the present invention, the valve plug includes a connecting portion and a sliding portion, the connecting portion is fixedly connected to the valve stem, the sliding portion moves to an end close to the valve seat, and the sliding portion fits into the second throttling hole; the sliding portion moves to an end away from the valve seat, and the sliding portion separates from the second throttling hole.

[0010] In some embodiments of the present invention, a combined sealing box is further provided at one end of the second through hole away from the valve seat. The combined sealing box is arranged between the valve cover and the valve stem, and includes a polytetrafluoroethylene packing near one end, a graphite packing at the other end, and a spacer ring between the polytetrafluoroethylene packing and the graphite packing.

[0011] In some embodiments of the present invention, a packing gland is further provided, which includes a pressing section extending into the second through hole, and a fixing section arranged outside the valve cover and fixedly connected to the valve cover.

[0012] In some embodiments of the present invention, the fixing section is connected to the valve cover bolt, and a disc spring is provided between the valve cover bolt and the fixing section.

[0013] In some embodiments of the present invention, a guide ring is further provided on a side of the second through hole close to the valve cage, and the guide ring is arranged between the valve stem and the valve cover.

[0014] In some embodiments of the present invention, a fixed pressure ring is provided between the valve cover and the valve cage. The fixed pressure ring is arranged in the valve body, one end of the fixed pressure ring is connected to the valve cover, and the other end is connected to the valve body. A seal is provided between the fixed pressure ring and the valve cage.

[0015] In some embodiments of the present invention, a sealing member is provided at the connection between the valve seat and the valve body, at the connection between the valve cover and the valve body, and at the connection between the valve cover and the fixed pressure ring.

[0016] The beneficial effects of the present invention are as follows: the present invention cleverly arranges multiple layers of valve cylinders and valve walls inside the valve body, so that the fluid is gradually depressurized when passing through multiple throttling holes, thereby avoiding large static pressure changes. It not only significantly reduces the instantaneous impact force when the bubble collapses, thereby reducing fluid dynamic noise and corrosion risks of components, but also optimizes the fluid flow path through the staggered throttling holes, thereby improving the accuracy of regulation. Compared with traditional control valves, the multi-stage control valve can more effectively stabilize the output, reduce noise, extend equipment life, and reduce the frequency and cost of daily maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 A partial cross-sectional structural diagram of a multi-stage pressure reduction and noise reduction regulating valve according to an embodiment of the present invention; Figure 2 A cross-sectional view of a multi-stage pressure reduction and noise reduction regulating valve in a working state according to an embodiment of the present invention; Figure 3 A cross-sectional view of the multi-stage pressure reduction and noise reduction regulating valve in another working state according to an embodiment of the present invention; Figure 4 Schematic diagram of the structure of the valve seat in the multi-stage pressure reduction and noise reduction regulating valve in an embodiment of the present invention; Figure 5 Schematic diagram of the structure of the valve cage, fixed pressure ring and valve plug in the multi-stage pressure reduction and noise reduction regulating valve in an embodiment of the present invention; Figure 6 Schematic diagram of the structure of the valve cover and its components in the multi-stage pressure reduction and noise reduction regulating valve in an embodiment of the present invention; Figure 7 In the embodiment of the present invention Figure 2 A magnified schematic diagram of the structure at A; Figure 8 In the embodiment of the present invention Figure 3A magnified schematic diagram of the structure at B; Figure 9 In the embodiment of the present invention Figure 3 A magnified schematic diagram of the structure at C; Figure 10 Schematic diagram of the structure of the sealing member in the multi-stage pressure reduction and noise reduction regulating valve in an embodiment of the present invention.

[0019] Figure numerals: 1. Valve body; 11. Fluid channel; 12. Fluid outlet; 13. Fluid inlet; 2. Valve seat; 21. Valve cylinder; 21a. First throttling hole; 22. First opening; 3. Valve cage; 31. Valve wall; 31a. Second throttling hole; 32. First through hole; 4. Valve cover; 41. Second through hole; 41a. Large diameter section; 41b. Small diameter section; 42. Chamber; 5. Valve plug; 51. Connecting part; 52. Sliding part; 6. Valve stem; 7. Combined sealing box; 71. Polytetrafluoroethylene packing; 72. Graphite packing; 73. Spacer ring; 74. Packing gland; 74a. Pressing section; 74b. Fixed section; 74c. Bolt; 74d. Disc spring; 75. Guide ring; 8. Fixed pressure ring; 9. Sealing element. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0021] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly attached to the other element or there may be an intermediate element. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only implementation methods.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used in this specification are for the purpose of describing specific embodiments only and are not intended to limit the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0023] like Figures 1 to 10 The multi-stage pressure reduction and noise reduction regulating valve shown includes: The valve body 1 has a fluid passage 11 inside, including a fluid outlet 12 and a fluid inlet 13; The valve seat 2 is provided inside the valve body 1 and includes a multi-layer valve cylinder 21 and a first opening 22 provided at one end of the valve cylinder 21. The multi-layer valve cylinder 21 is provided with a first throttle hole 21a, which is in communication with the fluid inlet 13. The cage 3, located within the valve body 1 and fixedly connected to the valve seat 2, comprises a multi-layered valve wall 31 with a first through-hole 32 at its center. One end of the first through-hole 32 is connected to the first opening 22. Each of the multi-layered valve wall 31 is provided with a second throttle hole 31a, which communicates with the fluid outlet 12. It should be noted that the number of layers in the valve cartridge 21 and the cage 3 can be configured to meet the actual noise reduction requirements for the fluid, and can include three, four, or other different numbers of layers. Furthermore, the shapes of the first and second throttle holes 21a, 31a can vary, including circular, elliptical, or other geometric shapes, depending on the flow characteristics of the regulating valve. The cage 3 and the valve cartridge 21 can also be constructed of materials with varying hardness or wear resistance, depending on the fluid properties.

[0024] The valve cover 4 is fixedly connected to the valve body 1. The valve body 1 has a second through hole 41 in the center. The second through hole 41 is divided into a large diameter section 41a and a small diameter section 41b. The large diameter section 41a is connected to the first through hole 32. The large diameter section 41a and the first through hole 32 form a chamber 42. The valve plug 5 is slidably disposed in the chamber 42 and can be relatively moved closer to or farther away from the valve cover 4; The valve stem 6 is fixedly connected to the valve plug 5, is slidably disposed in the second through hole 41, and can move relatively closer to or farther away from the valve seat 2; The valve cylinder 21 and valve wall 31 each have three layers. The first orifices 21a on two adjacent valve cylinders 21 are staggered, and the second orifices 31a on two adjacent cages 3 are staggered. Fluid flows through the inlet, passes through the first orifice 21a to the first opening 22, then through the first opening 22 into the first through-hole 32, and finally through the second orifice 31a to the outlet. It should be noted that the staggering of the first orifices 21a and the second orifice 31a can be varied, including staggered, random, or other staggered arrangements.

[0025] like Figures 1 to 3As shown, the flow of the regulating valve begins with the entry of fluid through the fluid inlet 13 of the valve body 1 into the internal flow channel. The fluid first enters the valve seat 2 of the multi-layered valve cylinder 21 through the staggered first throttle holes 21a, where it undergoes a throttling process and initially reduces its pressure. The fluid then enters the cage 3, formed by the multi-layered valve wall 31, through the first opening 22 at one end of the valve cylinder 21, and enters the cage 3, which is formed by the staggered second throttle holes 31a. The fluid then flows to the exterior of the cage 3, where its pressure is further regulated by the sophisticated throttle hole structure. From the first opening 22, the fluid enters the first through-hole 32 of the cage 3, where it continues to experience a stepwise pressure reduction through the multi-layer structure. This progressively reduces noise and pressure as it passes through each layer of throttle holes, ensuring fluid dynamic stability. During this time, the valve plug 5 slides within the chamber 42 formed by the valve bonnet 4, moving closer to or further away from the bonnet 4 to adjust the flow rate. The valve stem 6 extends through the second through-hole 41 in the bonnet 4, sliding to control the position of the valve plug 5 to achieve flow control. Finally, the fluid after multi-stage throttling flows out of the cage 3 and leaves the regulating valve through the fluid outlet 12 .

[0026] The present invention cleverly arranges multiple layers of valve cylinders 21 and valve walls 31 inside the valve body 1, so that the fluid is gradually depressurized when passing through multiple throttling holes, thereby avoiding large static pressure changes. This not only significantly reduces the instantaneous impact force when the bubble collapses, thereby reducing fluid dynamic noise and corrosion risks of components, but also optimizes the fluid flow path through the staggered throttling holes, thereby improving the accuracy of regulation. Compared with traditional control valves, this multi-stage control valve can more effectively stabilize output, reduce noise, extend equipment life, and reduce the frequency and cost of daily maintenance.

[0027] In traditional control valve designs, the arrangement of throttle holes is usually not targeted, which may lead to excessive local pressure drop and increase the risk of cavitation. Especially when the fluid passes through the throttling end face of the control valve, the flow rate increases sharply, and the static pressure drops sharply below the saturated vapor pressure of the fluid, which easily forms bubbles and then collapses in the pressure recovery area, generating extremely strong local impact and noise. Figure 4 、 Figure 5 As shown, the first throttle hole 21a and the second throttle hole 31a are both circular in shape, and the first throttle holes 21a or the second throttle holes 31a in the same layer are evenly arranged horizontally and vertically. By designing the first and second throttle holes 21a and 31a of the regulating valve to be circular in shape and arranging them evenly horizontally and vertically within the same layer, the uneven pressure distribution problem in traditional designs is solved. The circular structure can provide a more consistent flow path, making the turbulence formed when the fluid passes through the throttle hole more stable, effectively reducing the impact of sudden pressure drops, ensuring uniform pressure drop when the fluid passes through the same layer, reducing the formation and collapse of bubbles, and thus reducing noise and the degree of erosion of valve components.

[0028] When the valve is closed or close to closing, the rapid change in flow rate will cause large shock and vibration, posing a challenge to the long-term stability and reliability of the valve. Figure 2 As shown, the diameter of the innermost valve wall 31 is smaller than that of the innermost valve cylinder 21. When the valve plug 5 approaches the valve seat 2, the valve plug 5 abuts the valve seat 2. By designing the diameter of the innermost valve wall 31 to be smaller than that of the innermost valve cylinder 21, the valve plug 5 can accurately abut the valve seat 2 when it approaches the valve seat 2, allowing the valve plug 5 to fit more firmly on the valve seat 2, enhancing the reliability and durability of the seal. Under high pressure or high flow rate conditions, the close abutment between the valve plug 5 and the valve seat 2 effectively reduces the risk of fluid leakage, while also avoiding excessive wear and noise during the dynamic opening and closing of the valve.

[0029] The sealing and adjustment between the valve plug 5 and the valve seat 2 often rely on a relatively simple motion mechanism. This design may face problems such as loose sealing, increased wear and increased noise under high pressure difference and high flow rate conditions. In particular, when the valve plug 5 moves, the fluid dynamics may cause uneven pressure distribution, which limits the adjustment accuracy and sealing performance. Figure 2 、 Figure 3 As shown, the valve plug 5 includes a connecting portion 51 and a sliding portion 52. The connecting portion 51 is fixedly connected to the valve stem 6. When the sliding portion 52 moves to the end closer to the valve seat 2, it mates with the second throttle hole 31a. When the sliding portion 52 moves to the end farther from the valve seat 2, it separates from the second throttle hole 31a. The valve plug 5 is composed of the connecting portion 51 and the sliding portion 52. The connecting portion 51 is fixedly connected to the valve stem 6, ensuring stable positioning and effective transmission of the valve plug 5 during the adjustment process. The sliding portion 52 allows it to mate with the second throttle hole 31a at the end closer to the valve seat 2, providing a highly precise sealing effect. This mate ensures effective fluid isolation and reduces the risk of leakage, especially during flow control or valve closing. When the sliding portion 52 moves to the end farther from the valve seat 2, it separates from the second throttle hole 31a, allowing fluid to pass smoothly and achieving precise flow adjustment and control.

[0030] For the seal between the valve cover 4 and the valve stem 6, a single packing or a simple sealing structure is usually used, which may lead to a decrease in sealing effect, increased wear of the packing, and even leakage after long-term use. Figure 3 、 Figure 6 、 Figure 9As shown, the end of the second through-hole 41 away from the valve seat 2 also features a combined sealing ring 7. Disposed between the valve cover 4 and the valve stem 6, the combined sealing ring 7 includes a polytetrafluoroethylene (PTFE) packing 71 near one end, a graphite packing 72 at the other end, and a spacer ring 73 between the two packings. The combined sealing ring 7 at the end of the second through-hole 41 away from the valve seat 2 enhances sealing effectiveness and durability. The polytetrafluoroethylene (PTFE) packing 71 at one end offers superior chemical resistance and a low friction coefficient, ensuring stability and durability during daily operation. The graphite packing 72 at the other end offers excellent heat resistance and self-lubricating properties, enabling it to withstand fluid sealing requirements in high-temperature and high-pressure environments. The spacer ring 73 separates the polytetrafluoroethylene (PTFE) packing 71 and the graphite packing 72, allowing them to leverage their respective strengths, providing a multi-stage sealing effect. This ensures efficient sealing under varying operating conditions, reduces the risk of leakage due to packing wear, and extends the packing's service life.

[0031] When the fluid flows in a high-pressure or high-temperature environment, the packing may fail to seal due to material fatigue or wear, increasing the risk of leakage and affecting the overall performance and safety of the valve. Figure 3 、 Figure 6 and Figure 9 , further comprising a packing gland 74, which includes a pressing section 74a extending into the second through hole 41, and a fixing section 74b disposed on the outside of the valve cover 4 and fixedly connected to the valve cover 4. The packing gland 74, having the pressing section 74a extending into the second through hole 41, enhances the packing's pressing force and sealing effect. The pressing section 74a penetrates deeply into the second through hole 41, ensuring that the packing can tightly surround the valve stem 6 even at high flow rates or pressure changes, providing effective sealing support. The fixing section 74b is designed on the outside of the gland and fixedly connected to the valve cover 4, ensuring that the packing will not loosen or shift when subjected to pressure, thereby preventing packing wear or leakage.

[0032] The movement between the valve stem 6 and the valve cover 4 may be adversely affected by friction and vibration, especially in frequent operation or high-pressure environment, which may easily cause wear, deviation and fluid leakage. In order to improve the operational stability and extend the service life of the valve, Figure 3 、 Figure 9 As shown, fixed segment 74b is connected to bolt 74c of valve bonnet 4, with disc spring 74d interposed between bolt 74c and fixed segment 74b. A guide ring 75 is provided on the side of second through hole 41 near cage 3 to ensure precise positioning of valve stem 6 during movement within bonnet 4. Guide ring 75, positioned between valve stem 6 and bonnet 4, serves as a primary support structure, reducing lateral displacement and vibration of valve stem 6 during operation, ensuring smooth valve movement and accurate positioning, thereby minimizing frictional wear and tear on the equipment.

[0033] The movement of the valve stem 6 usually relies on a simple connection and support structure, which may cause the valve stem 6 to deflect or vibrate when facing a fluid environment with high flow rate or high pressure difference. Figure 3 、 Figure 6 As shown, a guide ring 75 is also provided on the side of the second through hole 41 near the cage 3, interposed between the valve stem 6 and the bonnet 4. The guide ring 75 ensures precise axial positioning of the valve stem 6 during movement, effectively reducing the possibility of deviation and vibration. The guide ring 75 provides a stable sliding support, ensuring smooth and precise movement of the valve stem 6, thereby maintaining concentricity between the valve plug 5 and the valve seat 2. The combined sealing gland 7 not only provides sealing but also provides support and positioning, ensuring the coaxial movement of the valve stem.

[0034] The connection between the valve cover 4 and the valve cage 3 may face problems such as poor sealing or loose components during operation due to insufficient structural complexity. Especially under high pressure or repeated operation conditions, seal failure may lead to fluid leakage and equipment performance degradation, increasing maintenance requirements and operating costs. In some embodiments of the present invention, such as Figures 1 to 3 、 Figure 5 、 Figure 7 、 Figure 8 、 Figure 10 As shown, a fixed pressure ring 8 is provided between the valve cover 4 and the valve cage 3. The fixed pressure ring 8 is arranged in the valve body 1, with one end connected to the valve cover 4 and the other end connected to the valve body 1. A seal 9 is provided between the fixed pressure ring 8 and the valve cage 3. This tight structure enhances the stability of the overall connection. The fixed pressure ring 8 not only provides additional physical support for the valve cover 4 and the valve cage 3, but also makes the internal distribution more uniform, reducing the risk of component displacement caused by operation or fluid pressure changes. The seal 9 provided between the fixed pressure ring 8 and the valve cage 3 further strengthens the sealing level to ensure that the fluid does not leak.

[0035] Pressure changes and long-term use may cause the sealing performance of the joints of various components to deteriorate, and even cause gasket wear or material aging, which not only causes fluid leakage, but also may affect the overall performance and safety of the valve. In some embodiments of the present invention, such as Figure 1 、 Figure 5 、 Figure 10 As shown, seals 9 are provided at the connection between the valve seat 2 and the valve body 1, at the connection between the valve cover 4 and the valve body 1, and at the connection between the valve cover 4 and the fixed pressure ring 8. By equipping the connection between the valve seat 2 and the valve body 1, the connection between the valve cover 4 and the valve body 1, and the connection between the valve cover 4 and the fixed pressure ring 8 with seals 9, a multi-level sealing effect of the entire system is ensured. These seals 9 can effectively offset the effects of pressure pulsation and temperature changes on the joint surfaces, thereby maintaining long-term sealing stability.

[0036] Those skilled in the art will appreciate that the present invention is not limited to the foregoing embodiments. The foregoing embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A multi-stage pressure reduction and noise reduction regulating valve, characterized in that: include: A valve body having a fluid passage therein, including a fluid outlet and a fluid inlet; a valve seat, disposed inside the valve body, comprising a multi-layer valve cylinder and a first opening disposed at one end of the valve cylinder, wherein each of the multi-layer valve cylinders is provided with a first throttle hole, the first throttle hole being in communication with the fluid inlet; a valve cage disposed inside the valve body and fixedly connected to the valve seat, comprising a multi-layer valve wall, wherein the valve wall has a first through hole at its center, one end of the first through hole is connected to the first opening, and each of the multi-layer valve wall has a second throttling hole, the second throttling hole being connected to the fluid outlet; a valve cover fixedly connected to the valve body, wherein the valve body has a second through hole at its center, the second through hole being divided into a large diameter section and a small diameter section, the large diameter section being connected to the first through hole, and the large diameter section and the first through hole forming a chamber; A valve plug is slidably disposed in the chamber and can be relatively moved closer to or farther away from the valve cover; a valve stem fixedly connected to the valve plug, slidably disposed in the second through hole, and capable of relatively approaching or moving away from the valve seat; Wherein, the valve cylinder and the valve wall both have three layers, the first throttling holes on two adjacent valve cylinders are staggered, and the second throttling holes on two adjacent valve cages are staggered; the fluid flows in through the inlet, flows through the first throttling hole to the first opening, passes through the first opening to the first through hole, and flows through the second throttling hole to the outlet.

2. The multi-stage pressure reduction and noise reduction regulating valve according to claim 1, characterized in that: The first throttle holes and the second throttle holes are both circular in shape, and the first throttle holes or the second throttle holes in the same layer are evenly arranged horizontally and vertically.

3. The multi-stage pressure reduction and noise reduction regulating valve according to claim 1, characterized in that: The innermost diameter of the valve wall is smaller than the innermost diameter of the valve cylinder. When the valve plug approaches the valve seat, the valve plug abuts against the valve seat.

4. The multi-stage pressure reduction and noise reduction regulating valve according to claim 1, characterized in that: The valve plug includes a connecting portion and a sliding portion, the connecting portion is fixedly connected to the valve stem, the sliding portion moves to an end close to the valve seat, and the sliding portion fits into the second throttle hole; the sliding portion moves to an end away from the valve seat, and the sliding portion separates from the second throttle hole.

5. The multi-stage pressure reduction and noise reduction regulating valve according to claim 1, characterized in that: A combined sealing box is provided at one end of the second through hole away from the valve seat. The combined sealing box is arranged between the valve cover and the valve stem, and includes a polytetrafluoroethylene packing near one end, a graphite packing at the other end, and a spacer ring between the polytetrafluoroethylene packing and the graphite packing.

6. The multi-stage pressure reduction and noise reduction regulating valve according to claim 5, characterized in that: A packing gland is also provided, which includes a pressing section extending into the second through hole, and a fixing section arranged outside the valve cover and fixedly connected to the valve cover.

7. The multi-stage pressure reduction and noise reduction regulating valve according to claim 6, characterized in that: The fixing section is connected to the valve cover bolt, and a disc spring is provided between the valve cover bolt and the fixing section.

8. The multi-stage pressure reduction and noise reduction regulating valve according to claim 1, characterized in that: The second through hole is further provided with a guide ring on a side close to the valve cage, and the guide ring is arranged between the valve stem and the valve cover.

9. The multi-stage pressure reduction and noise reduction regulating valve according to claim 1, characterized in that: A fixed pressure ring is further provided between the valve cover and the valve cage. The fixed pressure ring is arranged in the valve body, one end of the fixed pressure ring is connected to the valve cover, and the other end is connected to the valve body. A seal is provided between the fixed pressure ring and the valve cage.

10. The multi-stage pressure reduction and noise reduction regulating valve according to claim 1, characterized in that: The connection between the valve seat and the valve body, the connection between the valve cover and the valve body, and the connection between the valve cover and the fixed pressure ring are all provided with sealing elements.

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