Double-loop steam-water regulating valve

Abstract

The utility model discloses a double-loop steam-water regulating valve, belongs to the technical field of power station regulating valves, and aims to solve the problem that an inlet regulating valve of an existing steam-water separator is only suitable for one medium. Comprising a valve body, a rectifying sleeve and a valve seat sleeve are vertically arranged in the valve body, a plurality of first throttling hole sets are formed in the rectifying sleeve, a third throttling hole set and a plurality of fourth throttling holes are formed in the valve seat sleeve, the upper portion of the periphery of a large valve plug is in sliding fit with the rectifying sleeve, and the lower portion of the periphery of the large valve plug is in sliding fit with the inner periphery of the valve seat sleeve. A plurality of second throttling hole sets are formed in the lower portion of the large valve plug, the lower valve plug is in sliding fit with an inner hole of the large valve plug, a main valve port is formed between the periphery of the large valve plug and the valve seat sleeve, an auxiliary valve port is formed between the periphery of the small valve plug and the inner periphery of the large valve plug, a main loop is formed when the main valve port is opened, and an auxiliary loop is formed when the main valve port is closed and the auxiliary valve port is opened. And it can be guaranteed that good adjusting characteristics are achieved in various states that media are supercooled water, saturated water, vapor-liquid two phases, saturated steam and superheated steam.

Description

Technical Field

[0001] This utility model belongs to the field of power plant regulating valve technology, and in particular relates to a dual-circuit steam-water regulating valve. Background Technology

[0002] The inlet regulating valve of the steam-water separator is one of the important pieces of equipment in a steam power generation system. Its main function is to regulate the steam flow rate entering the steam-water separator, thereby precisely controlling the working state of the separator. During the start-up and shutdown of the unit, the medium undergoes a phase change process from water to steam. When entering the steam-water separator, it may present various states, including subcooled water, saturated water, two-phase steam, saturated steam, and superheated steam. This requires the inlet regulating valve of the steam-water separator to be able to adapt to the flow characteristics of various working media and to have reliable regulating capabilities.

[0003] The various control valves currently available on the market are usually only suitable for one state of one medium. When the medium has multiple states and multiple operating conditions, they are lacking in both regulation characteristics and operational stability, making it difficult to meet the system requirements. Utility Model Content

[0004] The purpose of this invention is to provide a dual-loop steam-water regulating valve to solve the problem that existing steam-water separator inlet regulating valves are only suitable for one medium. The technical solution adopted by this invention is as follows:

[0005] A dual-circuit steam-water regulating valve includes a valve body, which is a three-way component with a medium inlet, a medium outlet, and a shut-off control port. The valve cover closes the shut-off control port. A partition rib is provided inside the valve body, which divides the inner cavity of the valve body into an upper valve cavity and a lower valve cavity. The medium outlet is connected to the lower valve cavity, and the medium inlet and the shut-off control port are respectively connected to the upper valve cavity. A through hole is opened on the partition rib. The valve seat is a cup-shaped component that passes through the through hole and is sealed to the partition rib. A first sealing cone surface is provided at the top of the inner circumference of the valve seat. A plurality of third throttling holes are opened along the axial direction on the lower part of the side wall of the valve seat. A plurality of fourth throttling holes are provided on the bottom wall of the valve seat.

[0006] The rectifier sleeve is a cylindrical component. The lower end of the rectifier sleeve is fitted with the top stop of the valve seat sleeve. The valve cover closes the upper opening of the rectifier sleeve. The bottom of the rectifier sleeve is provided with a number of first throttling hole groups along the axial direction. The middle part of the rectifier sleeve is provided with a first flow passage hole group. The number of first throttling hole groups and the first flow passage hole groups are all located in the upper valve cavity.

[0007] The large valve plug is a cylindrical component with an upper sealing end. The outer circumferential surface of the large valve plug includes a first large diameter circumferential surface located at the top and a first small diameter circumferential surface located at the bottom. The first large diameter circumferential surface and the first small diameter circumferential surface are connected by a second sealing cone surface. The first large diameter circumferential surface slides with the inner circumference of the rectifier sleeve, and the first small diameter circumferential surface slides with the inner circumference of the valve seat sleeve. The second sealing cone surface abuts against the first sealing cone surface to seal or separate. Several second throttling orifice groups are provided axially on the side wall where the first small diameter circumferential surface is located. An annular step is provided on the inner circumference of the part where the first large diameter circumferential surface is located. A third sealing cone surface is provided at the upper end of the inner hole of the annular step. A small valve cavity is formed between the annular step and the top wall of the large valve plug. A second flow passage orifice group is provided on the side wall of the small valve cavity. When the second sealing cone surface abuts against the first sealing cone surface to seal, the first flow passage orifice group and the second flow passage orifice group are aligned and connected. The first large diameter circumferential surface closes several first throttling orifice groups. Several second throttling orifice groups are misaligned or partially overlapped with several third throttling orifice groups.

[0008] The inner bore of the annular step is axially spaced with several sets of valve plug guide grooves. An inner annular sealing band is formed at the lower end of each set of valve plug guide grooves on the inner circumference of the annular step. A small valve plug is located at the lower end of the valve stem. The outer circumferential surface of the small valve plug includes a second large diameter circumferential surface at the upper part and a second small diameter circumferential surface at the lower part. The second large diameter circumferential surface and the second small diameter circumferential surface are connected by a fourth sealing cone surface. The fourth sealing cone surface abuts against or separates from the third sealing cone surface. The distance from the third sealing cone surface to the top wall of the large valve plug is greater than the distance from the fourth sealing cone surface to the top of the small valve plug. The second small diameter circumferential surface slides in fit with the inner bore of the annular step. Several sets of valve stem throttling grooves are spaced apart along the axial direction on the small valve plug. An outer annular sealing band is formed at the lower end of each set of valve stem throttling grooves on the outer periphery of the small valve plug. When the fourth sealing cone surface abuts against the third sealing cone surface, several sets of valve stem throttling grooves and several sets of valve plug guide grooves are horizontally aligned one-to-one. Several inner annular sealing bands and several outer annular sealing bands abut against each other one-to-one. When the fourth sealing cone surface separates from the third sealing cone surface, several inner annular sealing bands and several outer annular sealing bands are misaligned. Several sets of valve stem throttling grooves and several sets of valve plug guide grooves are sequentially staggered and connected to form several pressure reducing channels.

[0009] The upper end of the valve stem passes through the top wall of the large valve plug and the valve cover in sequence, and is connected to the actuator.

[0010] Furthermore, the large valve plug includes an upper sleeve, several middle sleeves, and a lower sleeve that are threaded together from top to bottom. Several second throttling orifice groups are formed on the lower sleeve. Each middle sleeve has a valve plug guide groove group. The valve plug guide groove group is composed of several circumferentially evenly arranged first trapezoidal grooves. The first trapezoidal groove is composed of a guide straight section and a contraction section connected vertically. The valve stem throttling groove group is composed of several circumferentially evenly arranged second trapezoidal grooves. The second trapezoidal groove is composed of an expansion section, a straight section, and a contraction section connected from top to bottom. The small valve cavity is located inside the upper sleeve. A working gap is provided between the side wall of the small valve cavity and the second large diameter circumferential surface.

[0011] Furthermore, a process hole is provided at the top of the upper sleeve. The diameter of the process hole is larger than the diameter of the second largest circumferential surface. The sealing plate is threadedly connected to the upper sleeve and fills the process hole.

[0012] Furthermore, the sealing plate has pressure balance holes that allow air to pass through from top to bottom.

[0013] Furthermore, the valve stem is connected to the output end of the actuator via a guide coupling, and the actuator is supported on the valve cover by a support column. The guide coupling and the support column are in sliding engagement.

[0014] Furthermore, the valve cover is connected to the valve body by fastening bolts and fastening nuts.

[0015] Furthermore, a disc spring assembly is sleeved on the valve stem, and the valve stem is threadedly connected to the limit nut. The two ends of the disc spring assembly abut against the sealing plate and the limit nut, respectively.

[0016] Furthermore, the limit nut is fixed to the valve stem pin.

[0017] Furthermore, a sealing groove is machined on the lower end face of the valve cover, and the valve stem passes through the sealing groove through the valve cover. A sealing sleeve is provided in the sealing groove, and a retaining ring is threadedly connected to the valve cover. The retaining ring presses the sealing sleeve on the bottom surface of the sealing groove, and the valve cover and valve stem slide and seal through the sealing sleeve.

[0018] Furthermore, a stuffing box is machined on the upper surface of the valve cover, and the valve stem passes through the stuffing box through the valve cover. A packing assembly is provided inside the stuffing box, and a packing gland is connected to the valve cover. The packing gland presses the packing assembly onto the bottom surface of the stuffing box through a pressure sleeve, and the valve cover and valve stem are slidably sealed through the packing assembly.

[0019] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0020] 1. This utility model has two internally optimized throttling loops, which can ensure good regulation characteristics under various conditions such as subcooled water, saturated water, vapor-liquid two-phase, saturated steam and superheated steam.

[0021] 2. This utility model can be used as an inlet regulating valve for a steam-water separator to ensure the flow rate and quality of the medium entering the steam-water separator during system startup, shutdown, and load adjustment, thereby ensuring the stable operation of the steam-water separator and the safety of the system. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of this utility model;

[0023] Figure 2 This is a schematic diagram of the valve body structure;

[0024] Figure 3 This is a schematic diagram of the valve seat sleeve.

[0025] Figure 4 This is a schematic diagram of the rectifier sleeve;

[0026] Figure 5 This is a schematic diagram of the large valve plug;

[0027] Figure 6 This is a schematic diagram of the upper part of the structure;

[0028] Figure 7 This is the front sectional view of the middle section;

[0029] Figure 8 It is a top view of the middle section;

[0030] Figure 9 This is a sectional view of the lower part;

[0031] Figure 10 This is a schematic diagram of the valve stem structure;

[0032] Figure 11 yes Figure 10 AA section view;

[0033] Figure 12 This is a schematic diagram of the medium flow in the secondary loop;

[0034] Figure 13 This is a schematic diagram of the medium flow in the main circuit.

[0035] In the diagram, 1. Valve body, 2. Valve seat sleeve, 3. Large valve plug, 4. Valve stem, 5. Disc spring assembly, 6. Limit nut, 7. Rectifying sleeve, 8. Retaining ring, 9. Valve cover, 10. Fastening bolt, 11. Fastening nut, 12. Packing assembly, 13. Guide coupling, 14. Actuator, 15. Support, 16. Packing gland, 17. Pressure sleeve, 18. Sealing sleeve, 19. Cut-off control port, 20. Upper valve chamber, 21. Medium inlet, 22. Medium outlet, 23. Through hole, 24. Lower valve chamber, 25. Third throttling orifice assembly, 26. Fourth throttling orifice, 27. First sealing cone surface, 28. First flow passage orifice assembly, 29. First throttling orifice assembly, 30. Upper sleeve, 31. Middle sleeve, 32. Lower sleeve, 33. 34. Sealing plate; 35. Third sealing cone surface; 36. Air pressure balance hole; 37. First large diameter circumferential surface; 38. Second sealing cone surface; 39. First small diameter circumferential surface; 40. Process hole; 41. Second flow passage hole group; 42. Small valve cavity; 43. Valve plug guide groove group; 44. Second throttling hole group; 45. Small valve plug; 46. Fourth sealing cone surface; 47. Valve stem throttling groove group; 48. Outer circumferential annular sealing band; 49. Inner circumferential annular sealing band; 50. Annular step; 51. Second large diameter circumferential surface; 52. Second small diameter circumferential surface. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model is described below with reference to specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and not intended to limit the scope of the present utility model. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concept of the present utility model.

[0037] The connections mentioned in this utility model are divided into fixed connections and detachable connections. Fixed connections, also known as non-detachable connections, include but are not limited to conventional fixed connection methods such as folded connections, riveted connections, adhesive connections, and welded connections. Detachable connections include but are not limited to conventional disassembly methods such as bolt connections, snap-fit ​​connections, pin connections, and hinge connections. When a specific connection method is not explicitly defined, it is assumed that at least one existing connection method can be found to achieve this function, and those skilled in the art can choose according to their needs. For example, a welded connection can be chosen for a fixed connection, and a bolted connection can be chosen for a detachable connection.

[0038] The present invention will be further described in detail below with reference to the accompanying drawings. The following embodiments are explanations of the present invention, but the present invention is not limited to the following embodiments.

[0039] Example: Figures 1 to 13 As shown, a dual-circuit steam-water regulating valve includes a valve body 1, which is a three-way component with a medium inlet 21, a medium outlet 22, and a shut-off control port 19. A valve cover 9 closes the shut-off control port 19. A partition rib is provided inside the valve body 1, which divides the inner cavity of the valve body 1 into an upper valve cavity 20 and a lower valve cavity 24. The medium outlet 22 is connected to the lower valve cavity 24, and the medium inlet 21 and the shut-off control port 19 are respectively connected to the upper valve cavity 20. A through hole 23 is provided on the partition rib. The valve seat sleeve 2 is a cup-shaped component that passes through the through hole 23 and is sealed to the partition rib. A first sealing cone surface 27 is provided at the top of the inner circumference of the valve seat sleeve 2. A plurality of third throttling hole groups 25 are provided axially on the lower part of the side wall of the valve seat sleeve 2, and a plurality of fourth throttling holes 26 are provided on the bottom wall of the valve seat sleeve 2.

[0040] The rectifier sleeve 7 is a cylindrical component. The lower end of the rectifier sleeve 7 is fitted with the top stop of the valve seat sleeve 2. The valve cover 9 closes the upper opening of the rectifier sleeve 7. The bottom of the rectifier sleeve 7 is provided with a number of first throttling hole groups 29 along the axial direction to make the medium entering the valve cavity evenly distributed. The middle part of the rectifier sleeve 7 is provided with a first flow passage group 28. The number of first throttling hole groups 29 and the first flow passage group 28 are all located in the upper valve cavity 20.

[0041] The large valve plug 3 is a cylindrical component with an upper sealing end. The outer circumferential surface of the large valve plug 3 includes a first large-diameter circumferential surface 36 at the upper part and a first small-diameter circumferential surface 38 at the lower part. The diameter of the first small-diameter circumferential surface 38 is smaller than the diameter of the first large-diameter circumferential surface 36. The first large-diameter circumferential surface 36 and the first small-diameter circumferential surface 38 are connected by a second sealing cone surface 37. The first large-diameter circumferential surface 36 slides with the inner circumference of the rectifier sleeve 7, and the first small-diameter circumferential surface 38 slides with the inner circumference of the valve seat sleeve 2. The second sealing cone surface 37 abuts against or separates from the first sealing cone surface 27. Several axially spaced openings are formed on the side wall where the first small-diameter circumferential surface 38 is located. The second throttling orifice group 43 has an annular step 49 on the inner circumference of the part where the first large diameter circumferential surface 36 is located. The upper end of the inner hole of the annular step 49 has a third sealing cone surface 34. A small valve cavity 41 is formed between the annular step 49 and the top wall of the large valve plug 3. A second flow passage group 40 is opened on the side wall of the small valve cavity 41. When the second sealing cone surface 37 abuts and seals with the first sealing cone surface 27, the first flow passage group 28 and the second flow passage group 40 are aligned and connected. The first large diameter circumferential surface 36 closes several first throttling orifice groups 29. Several second throttling orifice groups 43 and several third throttling orifice groups 25 are misaligned or partially overlapped.

[0042] The inner hole of the annular step 49 is axially spaced with several sets of valve plug guide grooves 42. An inner annular sealing band 48 is formed at the lower end of each valve plug guide groove set 42 on the inner circumference of the annular step 49. A small valve plug 44 is provided at the lower end of the valve stem 4. The outer circumferential surface of the small valve plug 44 includes a second large diameter circumferential surface 50 at the upper part and a second small diameter circumferential surface 51 at the lower part. The diameter of the second small diameter circumferential surface 51 is smaller than the diameter of the second large diameter circumferential surface 50. The second large diameter circumferential surface 50 and the second small diameter circumferential surface 51 are connected by a fourth sealing cone surface 45. The fourth sealing cone surface 45 abuts against or separates from the third sealing cone surface 34. The distance from the third sealing cone surface 34 to the top wall of the large valve plug 3 is greater than the distance from the fourth sealing cone surface 45 to the top of the small valve plug 44, allowing the small valve plug 44 to move up and down. Between them, the second small diameter circumferential surface 51 slides with the inner hole of the annular step 49. Several sets of valve stem throttling groove groups 46 are spaced apart along the axial direction on the small valve plug 44. An outer annular sealing band 47 is formed at the lower end of each set of valve stem throttling groove groups 46 on the outer periphery of the small valve plug 44. When the fourth sealing cone surface 45 and the third sealing cone surface 34 abut and seal, several sets of valve stem throttling groove groups 46 and several sets of valve plug guide groove groups 42 are horizontally aligned one-to-one. Several inner annular sealing bands 48 and several outer annular sealing bands 47 abut one-to-one. When the fourth sealing cone surface 45 and the third sealing cone surface 34 are separated, several inner annular sealing bands 48 and several outer annular sealing bands 47 are misaligned. Several sets of valve stem throttling groove groups 46 and several sets of valve plug guide groove groups 42 are sequentially staggered and connected to form several pressure reducing channels.

[0043] The upper end of the valve stem 4 passes through the top wall of the large valve plug 3 and the valve cover 9 in sequence, and is connected to the actuator 14.

[0044] The first sealing cone surface 27 and the second sealing cone surface 37 form the main valve port, and the third sealing cone surface 34 and the fourth sealing cone surface 45 form the secondary valve port. This utility model includes two throttling circuits. One is the main circuit formed when the main valve port is open, consisting of the medium inlet 21, the upper valve chamber 20, several first throttling orifice groups 29, several second throttling orifice groups 43, several third throttling orifice groups 25 and several fourth throttling orifice groups 26, the lower valve chamber 24, and the medium outlet 22 connected in sequence. The other is the secondary circuit formed when the secondary valve port is open, consisting of the medium inlet 21, the upper valve chamber 20, the first flow passage group 28, the second flow passage group 40, several pressure reduction channels, several fourth throttling orifice groups 26, the lower valve chamber 24, and the medium outlet 22 connected in sequence. When the actuator 14 pushes the valve stem 4 downward to the lowest position, under the thrust of the actuator 14 and the disc spring group 5, both the main valve port and the secondary valve port are closed, and both the main circuit and the secondary circuit are cut off.

[0045] In the initial stage when the actuator 14 drives the valve stem 4 to slide upward, the secondary valve port opens while the main valve port remains closed. At this time, the medium flows in from the medium inlet 21, passes through the secondary circuit, and flows out from the medium outlet 22. The secondary circuit is suitable for working conditions where the working medium is water or a mixture of steam and water with a high water content.

[0046] When the small valve plug 44 abuts against the top wall of the large valve plug 3, the secondary circuit opens to its maximum. The actuator 14 continues to drive the valve stem 4 to move upward, and the main valve port can be opened. At this time, the first flow passage group 28 and the second flow passage group 40 are staggered and closed to each other. The medium flows in from the medium inlet 21, passes through the main circuit, and flows out from the medium outlet 22. The main circuit is suitable for working conditions where the working medium is steam or a steam-water mixture with a large amount of steam.

[0047] The advantages of this utility model are:

[0048] 1. This utility model has two internally optimized throttling loops, which can ensure good regulation characteristics under various conditions such as subcooled water, saturated water, vapor-liquid two-phase, saturated steam and superheated steam.

[0049] 2. This utility model can be used as an inlet regulating valve for a steam-water separator to ensure the flow rate and quality of the medium entering the steam-water separator during system startup, shutdown, and load adjustment, thereby ensuring the stable operation of the steam-water separator and the safety of the system.

[0050] The large valve plug 3 includes an upper sleeve 30, several middle sleeves 31, and a lower sleeve 32 connected sequentially from top to bottom by threads. Several second throttling orifice groups 43 are formed on the lower sleeve 32. Each middle sleeve 31 has a set of valve plug guide groove groups 42, which are composed of several circumferentially evenly arranged first trapezoidal grooves. The first trapezoidal grooves are composed of a guide straight section and a contraction section connected vertically. The valve stem throttling groove group 46 is composed of several circumferentially evenly arranged second trapezoidal grooves. The second trapezoidal grooves are composed of an expansion section, a straight section, and a contraction section connected sequentially from top to bottom. The small valve cavity 41 is located inside the upper sleeve 30, and a working gap is provided between the side wall of the small valve cavity 41 and the second large diameter circumferential surface 50. The upper sleeve 30, several middle sleeves 31, and lower sleeve 32 are connected by threaded engagement and locked with screws, which facilitates processing and assembly.

[0051] The upper sleeve 30 has a process hole 39 at its top end. The diameter of the process hole 39 is larger than the diameter of the second major circumferential surface 50. The sealing plate 33 is threaded to the upper sleeve 30 and fills the process hole 39. The function of the process hole 39 is to allow the small valve plug 44 to be inserted.

[0052] The sealing plate 33 has pressure balancing holes 35 that are open at both the top and bottom. The function of the pressure balancing holes 35 is to balance the pressure at the top and bottom of the sealing plate 33.

[0053] The valve stem 4 is connected to the output end of the actuator 14 via a guide coupling 13. The actuator 14 is supported on the valve cover 9 by a support column 15. The guide coupling 13 and the support column 15 are in sliding engagement. The function of the support column 15 is to provide support for the actuator 14, and the function of the guide coupling 13 is to provide guidance for the valve stem 4.

[0054] The valve cover 9 is connected to the valve body 1 by fastening bolts 10 and fastening nuts 11.

[0055] A disc spring assembly 5 is sleeved on the valve stem 4. The valve stem 4 is threadedly connected to the limit nut 6. The two ends of the disc spring assembly 5 abut against the sealing plate 33 and the limit nut 6, respectively. The function of the disc spring assembly 5 is to increase the axial thrust of the valve stem 4 on the large valve plug 3 while allowing relative sliding between the small valve plug 44 and the large valve plug 3. This keeps the main valve port tending to close and the auxiliary valve port tending to open. When the actuator 14 drives the valve stem 4 to slide upward, the auxiliary valve port is opened first.

[0056] The limit nut 6 is pinned to the valve stem 4 for fixation. This prevents the limit nut 6 from loosening.

[0057] A sealing groove is machined on the lower end surface of the valve cover 9. The valve stem 4 passes through the sealing groove through the valve cover 9. A sealing sleeve 18 is provided in the sealing groove. The retaining ring 8 is threadedly connected to the valve cover 9. The retaining ring 8 presses the sealing sleeve 18 on the bottom surface of the sealing groove. The valve cover 9 and the valve stem 4 are slidably sealed through the sealing sleeve 18.

[0058] A stuffing box is machined on the upper surface of the valve cover 9. The valve stem 4 passes through the stuffing box through the valve cover 9. A packing assembly 12 is provided inside the stuffing box. A packing gland 16 is connected to the valve cover 9. The packing gland 16 presses the packing assembly 12 onto the bottom surface of the stuffing box through a pressure sleeve 17. The valve cover 9 and the valve stem 4 are slidably sealed through the packing assembly 12.

[0059] The above embodiments are merely illustrative examples of the present utility model and do not limit its scope of protection. Those skilled in the art can make partial changes to it, as long as they do not exceed the spirit and essence of the present utility model, they are all within the scope of protection of the present utility model.

Claims

1. A dual-loop steam-water regulating valve, characterized in that: The valve includes a valve body (1), which is a three-way component with a medium inlet (21), a medium outlet (22), and a shut-off control port (19). The valve cover (9) closes the shut-off control port (19). The valve body (1) is provided with a partition, which divides the inner cavity of the valve body (1) into an upper valve chamber (20) and a lower valve chamber (24). The medium outlet (22) is connected to the lower valve chamber (24). The medium inlet (21) and the shut-off control port (19) are respectively... The valve seat sleeve (2) is connected to the upper valve chamber (20). A through hole (23) is provided on the partition. The valve seat sleeve (2) is a cup-shaped component. The valve seat sleeve (2) passes through the through hole (23). The valve seat sleeve (2) is sealed with the partition. The top of the inner circumference of the valve seat sleeve (2) is provided with a first sealing cone surface (27). The lower part of the side wall of the valve seat sleeve (2) is provided with a number of third throttling hole groups (25) along the axial direction. The bottom wall of the valve seat sleeve (2) is provided with a number of fourth throttling holes (26). The rectifier sleeve (7) is a cylindrical component. The lower end of the rectifier sleeve (7) is fitted with the top stop of the valve seat sleeve (2). The valve cover (9) closes the upper opening of the rectifier sleeve (7). The bottom of the rectifier sleeve (7) is provided with a number of first throttling hole groups (29) along the axial direction. The middle part of the rectifier sleeve (7) is provided with a first flow passage group (28). The number of first throttling hole groups (29) and the first flow passage group (28) are all located in the upper valve cavity (20). The large valve plug (3) is a cylindrical component with an upper sealing end. The outer circumferential surface of the large valve plug (3) includes a first large diameter circumferential surface (36) located at the top and a first small diameter circumferential surface (38) located at the bottom. The first large diameter circumferential surface (36) and the first small diameter circumferential surface (38) are connected by a second sealing cone surface (37). The first large diameter circumferential surface (36) slides with the inner circumference of the rectifier sleeve (7), and the first small diameter circumferential surface (38) slides with the inner circumference of the valve seat sleeve (2). The second sealing cone surface (37) abuts against or separates from the first sealing cone surface (27). Several second throttling hole groups (43) are provided axially on the side wall where the first small diameter circumferential surface (38) is located. An annular step (49) is provided on the inner circumference of the part where the surface (36) is located. A third sealing cone surface (34) is provided at the upper end of the inner hole of the annular step (49). A small valve cavity (41) is formed between the annular step (49) and the top wall of the large valve plug (3). A second flow hole group (40) is provided on the side wall of the small valve cavity (41). When the second sealing cone surface (37) abuts against the first sealing cone surface (27) to seal, the first flow hole group (28) and the second flow hole group (40) are aligned and connected. The first large diameter circumferential surface (36) closes several first throttling hole groups (29). Several second throttling hole groups (43) and several third throttling hole groups (25) are misaligned or partially overlapped. The inner hole of the annular step (49) is provided with several sets of valve plug guide grooves (42) spaced apart along the axial direction. The inner circumference of the annular step (49) forms an inner circumferential annular sealing band (48) at the lower end of each set of valve plug guide grooves (42). The lower end of the valve stem (4) is provided with a small valve plug (44). The outer circumferential surface of the small valve plug (44) includes a second large diameter circumferential surface (50) located at the upper part and a second small diameter circumferential surface (51) located at the lower part. The second large diameter circumferential surface (50) and the second small diameter circumferential surface (51) are connected by a fourth sealing cone surface (45). The fourth sealing cone surface (45) abuts against the third sealing cone surface (34) for sealing or separation. The distance from the third sealing cone surface (34) to the top wall of the large valve plug (3) is greater than the distance from the fourth sealing cone surface (45) to the top of the small valve plug (44). The second small diameter circumferential surface (51) and the annular step (49) are connected. The inner hole slides and fits, and the small valve plug (44) is provided with several sets of valve stem throttling grooves (46) spaced apart along the axial direction. The outer periphery of the small valve plug (44) forms an outer periphery annular sealing strip (47) at the lower end of each set of valve stem throttling grooves (46). When the fourth sealing cone surface (45) and the third sealing cone surface (34) abut and seal, the several sets of valve stem throttling grooves (46) and the several sets of valve plug guide grooves (42) are horizontally aligned one by one. The several inner periphery annular sealing strips (48) and the several outer periphery annular sealing strips (47) abut one by one. When the fourth sealing cone surface (45) and the third sealing cone surface (34) separate, the several inner periphery annular sealing strips (48) and the several outer periphery annular sealing strips (47) are misaligned. The several sets of valve stem throttling grooves (46) and the several sets of valve plug guide grooves (42) are sequentially interleaved and connected to form several pressure reducing channels. The upper end of the valve stem (4) passes through the top wall of the large valve plug (3) and the valve cover (9) in sequence, and is connected to the actuator (14).

2. The dual-circuit steam-water regulating valve according to claim 1, characterized in that: The large valve plug (3) includes an upper sleeve (30), several middle sleeves (31) and a lower sleeve (32) that are threaded together from top to bottom. Several second throttling hole groups (43) are opened on the lower sleeve (32). A valve plug guide groove group (42) is opened on each middle sleeve (31). The valve plug guide groove group (42) is composed of several circumferentially evenly arranged first trapezoidal grooves. The first trapezoidal groove is composed of a guide straight section and a contraction section connected from top to bottom. The valve stem throttling groove group (46) is composed of several circumferentially evenly arranged second trapezoidal grooves. The second trapezoidal groove is composed of an expansion section, a straight section and a contraction section connected from top to bottom. The small valve cavity (41) is located inside the upper sleeve (30). A working gap is provided between the side wall of the small valve cavity (41) and the second large diameter circumferential surface (50).

3. A dual-circuit steam-water regulating valve according to claim 2, characterized in that: The top of the upper sleeve (30) has a process hole (39), the diameter of which is larger than the diameter of the second major circumferential surface (50). The sealing plate (33) is threadedly connected to the upper sleeve (30) and fills the process hole (39).

4. A dual-circuit steam-water regulating valve according to claim 3, characterized in that: The sealing plate (33) has a pressure balance hole (35) that is open from top to bottom.

5. A dual-circuit steam-water regulating valve according to claim 1, characterized in that: The valve stem (4) is connected to the output end of the actuator (14) through a guide coupling (13). The actuator (14) is supported on the valve cover (9) by a support column (15). The guide coupling (13) and the support column (15) are in sliding fit.

6. A dual-circuit steam-water regulating valve according to claim 1, characterized in that: The valve cover (9) is connected to the valve body (1) by fastening bolts (10) and fastening nuts (11).

7. A dual-circuit steam-water regulating valve according to claim 1, characterized in that: A disc spring assembly (5) is sleeved on the valve stem (4). The valve stem (4) is threadedly connected to the limit nut (6). The two ends of the disc spring assembly (5) abut against the sealing plate (33) and the limit nut (6) respectively.

8. A dual-circuit steam-water regulating valve according to claim 7, characterized in that: The limit nut (6) is pinned to the valve stem (4) for fixation.

9. A dual-circuit steam-water regulating valve according to claim 1, characterized in that: A sealing groove is machined on the lower end face of the valve cover (9). The valve stem (4) passes through the valve cover (9) through the sealing groove. A sealing sleeve (18) is provided in the sealing groove. The retaining ring (8) is threadedly connected to the valve cover (9). The retaining ring (8) presses the sealing sleeve (18) on the bottom surface of the sealing groove. The valve cover (9) and the valve stem (4) are slidably sealed through the sealing sleeve (18).

10. A dual-circuit steam-water regulating valve according to any one of claims 1-9, characterized in that: A stuffing box is machined on the upper surface of the valve cover (9). The valve stem (4) passes through the stuffing box through the valve cover (9). A stuffing assembly (12) is provided inside the stuffing box. The stuffing gland (16) is connected to the valve cover (9). The stuffing gland (16) presses the stuffing assembly (12) onto the bottom surface of the stuffing box through the pressure sleeve (17). The valve cover (9) and the valve stem (4) are slidably sealed through the stuffing assembly (12).

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