A new self-acting recirculation valve

Abstract

The utility model relates to a new type self -force recirculation valve belongs to valve technical field, and the utility model discloses in order to overcome the problem existing in the similar valve of prior art. Including main valve body subassembly, sleeve, big valve plug, lower valve rod and lower valve seat, the upper portion of main valve body subassembly is equipped with the main valve port formed with big valve plug and valve body, the top of main valve body subassembly is fixed with guide bush through upper locating disc, is equipped with big spring between guide bush and big valve plug, the lower portion of main valve subassembly is equipped with sleeve and the lower valve seat of sliding arrangement in sleeve, the lower portion of lower valve rod forms lower valve port with lower valve seat, the upper portion of lower valve rod passes through big valve plug, and is linked with limiting nut, is equipped with vertical setting small spring between lower valve seat and sleeve, one side of sleeve communicates with bypass valve through bypass outlet pipe, when lower valve seat overcomes the elastic force of small spring and slides, bypass outlet pipe is closed. The utility model opens and closes through big spring and small spring to control main road and bypass respectively, eliminates the delay of recirculation bypass, and can quickly adapt system working condition change.

Description

Technical Field

[0001] This utility model belongs to the field of valve technology, and in particular relates to a novel self-regulating recirculation valve, which is suitable for fluid transportation systems such as boiler feed pumps and chemical process pumps. It is a new type of valve that can realize the self-regulating recirculation control of the medium, and is used to prevent the pump from being damaged by overheating, cavitation and other issues under low flow conditions, thus ensuring the stable operation of the system. Background Technology

[0002] Self-operated recirculation valves offer advantages such as requiring no external power (e.g., motors, cylinders), compact structure, and low cost, making them widely used in fluid transport systems in industries like power and chemicals. However, most existing self-operated recirculation valves employ a single spring to drive the valve core adjustment, which generally suffers from the following drawbacks: the single spring has a fixed stiffness, making it difficult for the valve core to quickly adapt to changes in operating conditions when system flow or pressure suddenly changes, resulting in delayed opening / closing of the recirculation bypass and causing short-term overheating of the pump body; simultaneously, the flow area adjustment range is narrow, especially under low-flow recirculation conditions, with flow fluctuation errors exceeding ±10%, making it difficult to meet high-precision process requirements.

[0003] Therefore, there is an urgent need to develop a new type of self-operated recirculation valve that has a fast response speed, high adjustment accuracy, reliable operation, and convenient maintenance. Utility Model Content

[0004] The purpose of this invention is to provide a novel self-regulating recirculation valve to overcome the problems existing in similar valves, achieving rapid response under changing operating conditions, high-precision flow regulation, and convenient maintenance. The technical solution adopted by this invention is as follows:

[0005] A novel self-operated recirculation valve includes a main valve body assembly, a sleeve, a large valve plug, a lower valve stem, and a lower valve seat. The main valve body assembly has an upper main valve body cavity and a lower main valve body cavity, which are coaxially arranged. The bottom diameter of the upper main valve body cavity is larger than the top diameter of the lower main valve body cavity. The medium outlet at the upper end and the medium inlet at the lower end of the main valve body assembly are connected through the upper and lower main valve body cavities. A first annular protrusion is provided on the bottom surface of the upper main valve body cavity, and a second annular protrusion is provided on the large valve plug. The first and second annular protrusions form the main valve port. An upper positioning plate is provided at the upper part of the upper main valve body cavity. The upper positioning plate has several flow holes. A guide sleeve is connected to the upper positioning plate, and the guide sleeve is connected to the large valve plug through a large spring.

[0006] The sleeve is fixed in the lower cavity of the main valve body by a lower positioning plate. The lower positioning plate has several flow holes. A flow channel is formed between the outer periphery of the sleeve and the side wall of the lower cavity of the main valve body. The upper end of the sleeve is sealed by an upper end cap. The inner hole of the sleeve is a stepped hole formed by an upper hole section and a lower hole section, and the diameter of the upper hole section is smaller than the diameter of the lower hole section. The lower valve seat is a cylindrical component. The bottom of the lower valve seat has a short shoulder. The outer periphery of the lower valve seat slides with the upper hole section. A small spring is sleeved on the outer periphery of the lower valve seat. The two ends of the small spring abut against the upper end face of the short shoulder and the bottom surface of the lower hole section, respectively. The lower end of the lower hole section has a limiting pressure ring to restrict the lower valve seat from sliding out. Several first throttling grooves are machined in the inner hole of the lower valve seat. A first radial convex ring is formed between two adjacent first throttling grooves. The top of the first throttling groove at the upper end has a first valve seat sealing cone surface. The lower valve stem includes a first thin rod section and a first thick rod section connected coaxially. The top of the first thick rod section has a first valve stem sealing cone surface. The sealing cone surface, the first valve seat sealing cone surface and the first valve stem sealing cone surface constitute the lower valve port. The outer periphery of the first thick rod section is machined with several second throttling grooves. A first radial flange is formed between two adjacent second throttling grooves. When the first valve seat sealing cone surface and the first valve stem sealing cone surface abut and seal, the several first throttling grooves and several second throttling grooves are aligned at the same height. Several first radial convex rings and several first radial flanges are matched one-to-one. When the first valve seat sealing cone surface and the first valve stem sealing cone surface separate, the several first throttling grooves and several second throttling grooves are staggered in sequence, so that a throttling gap is formed between the lower valve seat and the lower valve stem. The upper end of the first thin rod section passes through the large valve plug and is connected to the limit nut. The first thin rod section is slidably sealed with the upper end cover. A bypass valve assembly is provided on one side of the main valve body assembly. One side of the sleeve is connected to the inner cavity of the bypass valve assembly through a bypass outlet pipe. When the sleeve compresses the small spring and slides upward, the sleeve closes the bypass outlet pipe.

[0007] Furthermore, the bypass valve assembly includes a bypass valve body, a bypass valve seat, and a bypass valve plug. One side of the bypass valve body is connected to the main valve body assembly. The bypass valve body has an upper bypass chamber and a lower bypass chamber. The bypass outlet at the upper end of the bypass valve body and the bypass valve side port opened on one side of the lower bypass chamber are connected through the upper bypass chamber and the lower bypass chamber. The bypass valve seat is inserted into the upper bypass chamber. Several third throttling grooves are machined in the inner hole of the bypass valve seat. A second radial convex ring is formed between two adjacent third throttling grooves. A second valve seat sealing cone surface is provided at the top of the upper third throttling groove. The flange cover closes the lower opening of the lower bypass chamber. A flow shroud is provided in the lower bypass chamber. The flow shroud is a cylindrical component, including an upper thin-walled part and a lower thick-walled part. The upper end of the thin-walled part abuts coaxially with the bypass valve seat, and the lower end of the thick-walled part abuts with the flange cover. The outer periphery of the thick-walled part abuts against the side of the lower bypass chamber. The thick-walled part has an annular flow groove on its outer periphery. The inner hole of the thick-walled part is a stepped hole formed by the upper and lower holes of the first hole segment and the second hole segment. The diameter of the first hole segment is larger than that of the second hole segment. The first hole segment and the second hole segment are connected by a rounded corner structure. The bypass valve plug includes a throttling rod segment, a second thin rod segment and a second thick rod segment connected from top to bottom. The second thick rod segment includes a first cylindrical part and a second cylindrical part arranged vertically. The diameter of the first cylindrical part is larger than that of the second cylindrical part. The outer peripheries of the first cylindrical part and the second cylindrical part are connected by a transition conical surface. The first cylindrical part and the first hole segment are in sliding fit, and the second cylindrical part and the second hole segment are in sliding fit. A pressure cavity is formed between the rounded corner structure and the transition conical surface. Several flow holes communicating with the pressure cavity are machined on the bottom surface of the annular flow groove. The lower cavity of the main valve body is connected to the annular flow groove through a connecting pipe.

[0008] The throttling rod section slides into the inner hole of the bypass valve seat. The top of the throttling rod section is provided with a second valve stem sealing cone surface. The second valve seat sealing cone surface and the second valve stem sealing cone surface form the bypass valve port. The outer periphery of the second throttling rod section is machined with several fourth throttling grooves. A second radial flange is formed between two adjacent fourth throttling grooves. When the bypass valve plug slides upward, the second valve seat sealing cone surface and the second valve stem sealing cone surface abut and seal. The several third throttling grooves and several fourth throttling grooves are aligned at the same height. The several second radial convex rings and several second radial flanges are matched one by one. When the bypass valve plug abuts against the flange cover, the second valve seat sealing cone surface and the second valve stem sealing cone surface separate. The several third throttling grooves and several fourth throttling grooves are staggered in sequence, and a throttling gap is formed between the throttling rod section and the bypass valve seat.

[0009] A working gap is provided between the outer periphery of the thin-walled section and the side wall of the bypass lower cavity, and a working gap is provided between the outer periphery of the second thin rod section and the inner periphery of the thin-walled section. Several throttling holes are provided on the side wall of the thin-walled section, and a permeable first pressure balance hole is opened along the axis on the bypass valve plug.

[0010] Furthermore, the main valve body assembly includes a lower valve body and an upper valve body. The lower cavity of the main valve body is located inside the lower valve body. The lower opening of the lower valve body is the medium inlet. The top of the lower valve body is provided with a countersunk platform, which is connected to the medium inlet through the lower cavity of the main valve body. The lower end face of the upper valve body is provided with a frustoconical cavity that gradually converges from bottom to top. The upper opening of the upper valve body is the medium outlet, which is connected to the frustoconical cavity. The upper and lower valve bodies are assembled vertically to form the main valve body assembly. The frustoconical cavity and the countersunk platform are combined to form the upper cavity of the main valve body. A main valve side port is provided on one side of the lower valve body. A bypass outlet pipe passes through the main valve side port and exits the main valve body assembly.

[0011] Furthermore, the bypass valve body is connected to the main valve body assembly via a bypass flange pipe, and the inner cavity of the bypass valve body is connected to the bypass outlet pipe via the inner hole of the bypass flange pipe.

[0012] Furthermore, the large valve plug includes a valve plug tray and a valve plug cover. The valve plug tray is disc-shaped, and the valve plug cover is annular disc-shaped. The valve plug cover and the valve plug tray are coaxially fitted with a stop. The first thin rod section passes through the valve plug tray and is connected to the limit nut. The inner diameter of the second annular protrusion is larger than the outer diameter of the valve plug tray. The second annular protrusion is set on the lower end face of the valve plug cover.

[0013] Furthermore, the upper positioning plate and the upper valve body are coaxially fitted with a stop, and the guide sleeve is coaxially fitted with the upper positioning plate. The guide sleeve has a first tube structure extending downward, and the valve plug cover has a second tube structure extending upward. The inner circumference of the second tube structure is slidably fitted with the outer circumference of the first tube structure. The top end of the first tube structure is provided with several second pressure balance holes. The upper end of the large spring extends into the first tube structure, and the lower end of the large spring abuts against the valve plug tray.

[0014] Furthermore, a bypass sleeve is provided at the top of the bypass cavity, and the bypass sleeve and the bypass valve seat are mutually restrained and limited.

[0015] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0016] 1. This utility model uses a large spring and a small spring to control the opening and closing of the main circuit and the bypass respectively, eliminating the delay of the recirculation bypass and enabling it to quickly adapt to changes in system operating conditions.

[0017] 2. An adjustment mechanism consisting of a bypass valve seat and a bypass valve plug that can operate simultaneously was added to the original recirculation bypass, which further improved the response speed, increased the number of throttling stages, and improved the control accuracy and adjustment range. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of this utility model;

[0019] Figure 2 This is a structural schematic diagram of the main valve body assembly;

[0020] Figure 3 This is a schematic diagram of the lower valve body;

[0021] Figure 4 This is a schematic diagram of the upper valve body;

[0022] Figure 5 This is a schematic diagram of the large valve plug;

[0023] Figure 6 This is a schematic diagram of the lower valve seat;

[0024] Figure 7 This is a schematic diagram of the lower valve stem.

[0025] Figure 8 This is a schematic diagram of the sleeve structure;

[0026] Figure 9 This is a schematic diagram of the bypass valve body;

[0027] Figure 10 This is a schematic diagram of the fairing structure;

[0028] Figure 11 This is a schematic diagram of the bypass valve plug;

[0029] Figure 12 This is a schematic diagram of the bypass valve seat;

[0030] Figure 13 This is a schematic diagram of the guide sleeve structure;

[0031] Figure 14 yes Figure 1 Enlarged view of point A.

[0032] 1. Main valve body assembly, 2. Limiting pressure ring, 3. Lower positioning plate, 4. Small spring, 5. Lower valve seat, 6. Lower valve stem, 7. Sleeve, 8. Upper end cover, 9. Large valve plug, 10. Limiting nut, 11. Large spring, 12. Guide sleeve, 13. Upper positioning plate, 14. Upper valve body, 15. Bypass outlet pipe, 16. Bypass flange pipe, 17. Connecting pipe, 18. Bypass valve body, 19. Bypass pressure sleeve, 20. Bypass valve seat, 21. Bypass valve plug, 22. Radiator, 2 3. Flange cover; 24. Main valve port; 25. Lower valve port; 26. Bypass valve port; 27. Medium inlet; 28. Lower cavity of main valve body; 29. ​​Upper cavity of main valve body; 30. Countersunk platform; 31. Side port of main valve; 32. Frustum cavity; 33. Lower valve body; 34. Medium outlet; 35. Valve plug tray; 36. Valve plug cover; 37. First annular protrusion; 38. Second pipe structure; 39. First throttling groove; 40. First thick rod section; 41. First radial flange; 42. Bypass. 43. Bypass upper chamber, 44. Bypass valve side port, 45. Bypass lower chamber, 46. Annular flow groove, 47. First valve seat sealing cone surface, 48. First radial convex ring, 49. Short shoulder, 50. First thin rod section, 51. First valve stem sealing cone surface, 52. Second throttling groove, 53. Upper hole section, 54. Lower hole section, 55. Thin-walled part, 56. Thick-walled part, 57. Throttling orifice, 58. First hole section, 59. Second hole section, 60. Flow passage orifice, 61. 62. Second thin rod section, 63. Second thick rod section, 64. First cylindrical part, 65. Transition cone surface, 66. Second cylindrical part, 67. Second radial flange, 68. Fourth throttling groove, 69. Second valve stem sealing cone surface, 70. First pressure balance hole, 71. Second valve seat sealing cone surface, 72. Third throttling groove, 73. Second radial convex ring, 74. First tube body structure, 75. Second pressure balance hole, 76. Pressure chamber, 77. Second annular protrusion. Detailed Implementation

[0033] 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.

[0034] 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.

[0035] 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.

[0036] Example: Figures 1 to 14 As shown, a novel self-regulating recirculation valve includes a main valve body assembly 1, a sleeve 7, a large valve plug 9, a lower valve stem 6, and a lower valve seat 5. The main valve body assembly 1 has an upper main valve body chamber 29 and a lower main valve body chamber 28, which are coaxially arranged. The bottom diameter of the upper main valve body chamber 29 is larger than the top diameter of the lower main valve body chamber 28. The medium outlet 34 at the upper end and the medium inlet 27 at the lower end of the main valve body assembly 1 pass through the upper main valve body chamber. 29 is connected to the lower cavity 28 of the main valve body. The bottom surface of the upper cavity 29 of the main valve body is provided with a first annular protrusion 37 and the large valve plug 9 is provided with a second annular protrusion 77. The first annular protrusion 37 and the second annular protrusion 77 form the main valve port 24. The upper part of the upper cavity 29 of the main valve body is provided with an upper positioning plate 13. The upper positioning plate 13 is provided with several flow holes. The guide sleeve 12 is connected to the upper positioning plate 13. The guide sleeve 12 is connected to the large valve plug 9 through a large spring 11.

[0037] The sleeve 7 is fixed in the lower cavity 28 of the main valve body by the lower positioning plate 3. The lower positioning plate 3 is provided with several flow holes. A flow channel is formed between the outer periphery of the sleeve 7 and the side wall of the lower cavity 28 of the main valve body. The upper end of the sleeve 7 is sealed by the upper end cap 8. The inner hole of the sleeve 7 is a stepped hole formed by the upper hole section 53 and the lower hole section 54, and the diameter of the upper hole section 53 is smaller than the diameter of the lower hole section 54. The lower valve seat 5 is a cylindrical component. The bottom of the lower valve seat 5 is provided with a short shoulder 49. The outer periphery of the lower valve seat 5 slides with the upper hole section 53. A small spring is sleeved on the outer periphery of the lower valve seat 5. 4. The two ends of the small spring 4 abut against the upper end face of the short shoulder 49 and the bottom surface of the lower hole section 54, respectively. The lower end of the lower hole section 54 is provided with a limiting pressure ring 2 to restrict the lower valve seat 5 from sliding out. Several first throttling grooves 39 are machined in the inner hole of the lower valve seat 5. A first radial convex ring 48 is formed between two adjacent first throttling grooves 39. The top of the first throttling groove 39 at the upper end is provided with a first valve seat sealing cone surface 47. The lower valve stem 6 includes a first thin rod section 50 and a first thick rod section 40 connected coaxially. The top of the first thick rod section 40 is provided with a first valve stem sealing cone surface 47. The sealing cone surface 51, the first valve seat sealing cone surface 47, and the first valve stem sealing cone surface 51 constitute the lower valve port 25. The outer periphery of the first thick rod section 40 is machined with several second throttling grooves 52. A first radial flange 41 is formed between two adjacent second throttling grooves 52. When the first valve seat sealing cone surface 47 and the first valve stem sealing cone surface 51 abut and seal, the several first throttling grooves 39 and several second throttling grooves 52 are aligned at the same height. Several first radial convex rings 48 and several first radial flanges 41 are correspondingly engaged. The first valve seat sealing cone surface 47 and... When the sealing cone surface 51 of the first valve stem separates, several first throttling grooves 39 and several second throttling grooves 52 are staggered in sequence, so that a throttling gap is formed between the lower valve seat 5 and the lower valve stem 6. The upper end of the first thin rod section 50 passes through the large valve plug 9 and is connected to the limit nut 10. The first thin rod section 50 is slidably sealed with the upper end cover 8. A bypass valve assembly is provided on one side of the main valve body assembly 1. One side of the sleeve 7 is connected to the inner cavity of the bypass valve assembly through the bypass outlet pipe 15. When the sleeve 7 compresses the small spring 4 and slides upward, the sleeve 7 closes the bypass outlet pipe 15.

[0038] The bypass valve assembly includes a bypass valve body 18, a bypass valve seat 20, and a bypass valve plug 21. One side of the bypass valve body 18 is connected to the main valve body assembly 1. The bypass valve body 18 has an upper bypass chamber 43 and a lower bypass chamber 45. The bypass outlet 42 at the upper end of the bypass valve body 18 and the bypass valve side port 44 opened on one side of the lower bypass chamber 45 are connected through the upper bypass chamber 43 and the lower bypass chamber 45. The bypass valve seat 20 is inserted into the upper bypass chamber 43. Several third throttling grooves 72 are machined in the inner hole of the bypass valve seat 20. Two adjacent third throttling grooves 72 are connected to each other. A second radial convex ring 73 is formed between the three throttling grooves 72. A second valve seat sealing cone surface 71 is provided at the top of the third throttling groove 72 located at the upper end. The flange cover 23 closes the lower opening of the bypass lower cavity 45. A shunting shroud 22 is provided inside the bypass lower cavity 45. The shunting shroud 22 is a cylindrical component, including an upper thin-walled part 55 and a lower thick-walled part 56. The upper end of the thin-walled part 55 abuts coaxially with the bypass valve seat 20, and the lower end of the thick-walled part 56 abuts with the flange cover 23. The outer periphery of the thick-walled part 56 abuts against the side of the bypass lower cavity 45. The thick-walled portion 56 has an annular flow groove 46 on its outer periphery. The inner hole of the thick-walled portion 56 is a stepped hole formed by the upper and lower arrangement of the first hole segment 58 and the second hole segment 59. The diameter of the first hole segment 58 is larger than the diameter of the second hole segment 59. The first hole segment 58 and the second hole segment 59 are connected by a rounded corner structure. The bypass valve plug 21 includes a throttling rod segment 61, a second thin rod segment 62 and a second thick rod segment 63 connected from top to bottom. The second thick rod segment 63 includes a first cylindrical portion 64 and a second cylindrical portion 66 arranged vertically. The diameter of the first cylindrical part 64 is larger than the diameter of the second cylindrical part 66. The outer peripheries of the first cylindrical part 64 and the second cylindrical part 66 are connected by a transition conical surface 65. The first cylindrical part 64 and the first hole section 58 are in sliding fit, and the second cylindrical part 66 and the second hole section 59 are in sliding fit. A pressure cavity 76 is formed between the rounded corner structure and the transition conical surface 65. A plurality of flow holes 60 communicating with the pressure cavity 76 are machined on the bottom surface of the annular flow groove 46. The lower cavity 28 of the main valve body is connected to the annular flow groove 46 through a connecting pipe 17.

[0039] The throttling rod section 61 slides into the inner hole of the bypass valve seat 20. The top of the throttling rod section 61 is provided with a second valve stem sealing cone surface 69. The second valve seat sealing cone surface 71 and the second valve stem sealing cone surface 69 form a bypass valve port 26. The outer periphery of the second throttling rod section 61 is machined with a number of fourth throttling grooves 68. A second radial flange 67 is formed between two adjacent fourth throttling grooves 68. When the bypass valve plug 21 slides upward, so that the second valve seat sealing cone surface 71 and the second valve stem sealing cone surface 69 abut and seal, the number of third throttling grooves 72 and the number of fourth throttling grooves 68 are aligned at the same height. The number of second radial convex rings 73 and the number of second radial flanges 67 are matched one-to-one. When the bypass valve plug 21 abuts against the flange cover 23, the second valve seat sealing cone surface 71 and the second valve stem sealing cone surface 69 separate, and the number of third throttling grooves 72 and the number of fourth throttling grooves 68 are staggered in sequence, forming a throttling gap between the throttling rod section 61 and the bypass valve seat 20.

[0040] A working gap is provided between the outer periphery of the thin-walled portion 55 and the side wall of the bypass lower cavity 45. A working gap is provided between the outer periphery of the second thin rod section 62 and the inner periphery of the thin-walled portion 55. Several throttling holes 57 are provided on the side wall of the thin-walled portion 55. A permeable first pressure balance hole 70 is opened along the axis on the bypass valve plug 21.

[0041] The main valve body assembly 1 includes a lower valve body 33 and an upper valve body 14. The lower cavity 28 of the main valve body is located inside the lower valve body 33. The lower opening of the lower valve body 33 is the medium inlet 27. The top of the lower valve body 33 is provided with a countersunk platform 30. The countersunk platform 30 and the medium inlet 27 are connected through the lower cavity 28 of the main valve body. The lower end face of the upper valve body 14 is provided with a frustum-shaped cavity 32 that gradually converges from bottom to top. The upper opening of the upper valve body 14 is the medium outlet 34. The medium outlet 34 is connected to the frustum-shaped cavity 32. The upper valve body 14 and the lower valve body 33 are connected vertically to form the main valve body assembly 1. The frustum-shaped cavity 32 and the countersunk platform 30 are combined to form the upper cavity 29 of the main valve body. The lower valve body 33 is provided with a main valve side port 31 on one side. The bypass outlet pipe 15 passes through the main valve side port 31 and exits the main valve body assembly 1.

[0042] The bypass valve body 18 is connected to the main valve body assembly 1 via the bypass flange pipe 16, and the inner cavity of the bypass valve body 18 is connected to the bypass outlet pipe 15 via the inner hole of the bypass flange pipe 16.

[0043] The large valve plug 9 includes a valve plug tray 35 and a valve plug cover 36. The valve plug tray 35 is disc-shaped, and the valve plug cover 36 is annular. The valve plug cover 36 and the valve plug tray 35 are coaxially fitted with a stop. The first thin rod section 50 passes through the valve plug tray 35 and is connected to the limit nut 10. The inner diameter of the second annular protrusion 77 is larger than the outer diameter of the valve plug tray 35. The second annular protrusion 77 is located on the lower end face of the valve plug cover 36.

[0044] The upper positioning plate 13 and the upper valve body 14 are coaxially fitted with a stop, and the guide sleeve 12 is coaxially fitted with the upper positioning plate 13. The guide sleeve 12 is provided with a first tube structure 74 extending downward, and the valve plug cover 36 is provided with a second tube structure 38 extending upward. The inner circumference of the second tube structure 38 is slidably fitted with the outer circumference of the first tube structure 74. The top end of the first tube structure 74 is provided with several second pressure balance holes 75. The upper end of the large spring 11 extends into the first tube structure 74, and the lower end of the large spring 11 abuts against the valve plug tray 35.

[0045] The top of the bypass upper cavity 43 is provided with a bypass pressure sleeve 19, which abuts against the bypass valve seat 20 to limit movement.

[0046] This utility model relates to a novel self-operated recirculation valve, which includes two circuits: a main circuit and a recirculation circuit. The main valve port 24 of the main circuit is controlled to open and close by a large valve plug 9. The recirculation circuit includes a lower valve port 25 and a bypass valve port 26 connected in series, which are controlled to open and close by a lower valve stem 6 and a bypass valve plug 21, respectively.

[0047] This valve can automatically switch its operating status according to changes in the outlet flow rate of the water pump.

[0048] When the feedwater pump is operating normally, the flow rate at the medium inlet is higher than the set value. Under pressure, this pushes the large valve plug 9 upward, compressing the large spring 11 and opening the main valve port 24, connecting the main circuit and allowing feedwater to flow to the boiler. The lower valve stem 6, driven by the large valve plug 9, moves upward, sealing the lower valve port 25 and pulling the lower valve seat 5 upward, closing the bypass outlet pipe 15 and shutting off the upstream stage of the recirculation circuit. Simultaneously, feedwater also enters the pressure chamber 76 through the connecting pipe 17, pushing the bypass valve plug 21 upward, sealing the bypass valve port 26, and shutting off the downstream stage of the recirculation circuit. At this time, all flow passes through the main circuit.

[0049] When the feedwater pump operates at low load, the flow rate at the medium inlet is lower than the set value, and the feedwater pressure is less than the thrust of the large spring 11. The large valve plug 9 moves downward, sealing the main valve port 24, and the main valve circuit is closed. The lower valve stem 6 and the lower valve seat 5 slide downward under the elastic force of the small spring 4, opening the lower valve port 25 and connecting the upstream stage of the recirculation circuit. At the same time, the bypass valve plug 21 also falls back due to its own weight as the feedwater pressure decreases, opening the bypass valve port 26 and connecting the downstream stage of the recirculation circuit. The feedwater flows through the multi-stage throttling channels connected in series in the upstream and downstream stages to the deaerator after pressure reduction. At this time, all flow passes through the recirculation circuit.

[0050] Compared with the prior art, the advantages of this utility model are:

[0051] 1. This utility model uses a large spring 11 and a small spring 3 to control the opening and closing of the main circuit and the bypass respectively, eliminating the delay of the recirculation bypass and enabling it to quickly adapt to changes in system operating conditions.

[0052] 2. An adjustment mechanism consisting of a bypass valve seat 20 and a bypass valve plug 21, which can operate simultaneously, was added to the original recirculation bypass, further improving the response speed. At the same time, the number of throttling stages was increased, improving the control accuracy and adjustment range.

[0053] 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 novel self-regulating recirculation valve, characterized in that: The main valve body assembly includes a main valve body assembly (1), a sleeve (7), a large valve plug (9), a lower valve stem (6), and a lower valve seat (5). The main valve body assembly (1) is provided with an upper main valve body cavity (29) and a lower main valve body cavity (28). The upper main valve body cavity (29) and the lower main valve body cavity (28) are coaxially arranged, and the bottom diameter of the upper main valve body cavity (29) is larger than the top diameter of the lower main valve body cavity (28). The medium outlet (34) at the upper end and the medium inlet (27) at the lower end of the main valve body assembly (1) pass through the upper main valve body cavity (29) and the lower main valve body cavity (28). The cavity (28) is connected, and a first annular protrusion (37) is provided on the bottom surface of the upper cavity (29) of the main valve body, and a second annular protrusion (77) is provided on the large valve plug (9). The first annular protrusion (37) and the second annular protrusion (77) form the main valve port (24). An upper positioning plate (13) is provided at the upper part of the upper cavity (29) of the main valve body. Several flow holes are provided on the upper positioning plate (13). The guide sleeve (12) is connected to the upper positioning plate (13). The guide sleeve (12) is connected to the large valve plug (9) through a large spring (11). The sleeve (7) is fixed in the lower cavity (28) of the main valve body by the lower positioning plate (3). The lower positioning plate (3) is provided with several flow holes. A flow channel is formed between the outer periphery of the sleeve (7) and the side wall of the lower cavity (28) of the main valve body. The upper end of the sleeve (7) is sealed by the upper end cap (8). The inner hole of the sleeve (7) is a stepped hole composed of the upper hole section (53) and the lower hole section (54). The diameter of the upper hole section (53) is smaller than the diameter of the lower hole section (54). The lower valve seat (5) is a cylindrical component. The bottom of the lower valve seat (5) is provided with a short shoulder (49). The outer periphery of the lower valve seat (5) slides with the upper hole section (53). The outer periphery of the lower valve seat (5) is sleeved with There is a small spring (4), the two ends of which abut against the upper end face of the short shoulder (49) and the bottom surface of the lower hole section (54) respectively. The lower end of the lower hole section (54) is provided with a limiting pressure ring (2) to restrict the lower valve seat (5) from sliding out. Several first throttling grooves (39) are machined in the inner hole of the lower valve seat (5). A first radial convex ring (48) is formed between two adjacent first throttling grooves (39). The top of the first throttling groove (39) located at the upper end is provided with a first valve seat sealing cone surface (47). The lower valve rod (6) includes a first thin rod section (50) and a first thick rod section (40) connected coaxially. The top of the first thick rod section (40) is provided with a first valve seat sealing cone surface (47). A valve stem sealing cone (51), a first valve seat sealing cone (47), and a first valve stem sealing cone (51) constitute the lower valve port (25). The outer periphery of the first thick rod section (40) is machined with several second throttling grooves (52). A first radial flange (41) is formed between two adjacent second throttling grooves (52). When the first valve seat sealing cone (47) and the first valve stem sealing cone (51) abut and seal, several first throttling grooves (39) and several second throttling grooves (52) are aligned at the same height. Several first radial convex rings (48) and several first radial flanges (41) are matched one-to-one. The first valve seat sealing cone (47) and... When the first valve stem sealing cone (51) separates, several first throttling grooves (39) and several second throttling grooves (52) are staggered in sequence, so that a throttling gap is formed between the lower valve seat (5) and the lower valve stem (6). The upper end of the first thin rod section (50) passes through the large valve plug (9) and is connected to the limit nut (10). The first thin rod section (50) and the upper end cover (8) are slidably sealed together. A bypass valve assembly is provided on one side of the main valve body assembly (1). One side of the sleeve (7) is connected to the inner cavity of the bypass valve assembly through the bypass outlet pipe (15). When the sleeve (7) compresses the small spring (4) and slides upward, the sleeve (7) closes the bypass outlet pipe (15).

2. The novel self-regulating recirculation valve according to claim 1, characterized in that: The bypass valve assembly includes a bypass valve body (18), a bypass valve seat (20), and a bypass valve plug (21). One side of the bypass valve body (18) is connected to the main valve body assembly (1). The bypass valve body (18) is provided with an upper bypass chamber (43) and a lower bypass chamber (45). The bypass outlet (42) at the upper end of the bypass valve body (18) and the bypass valve side port (44) opened on one side of the lower bypass chamber (45) are connected through the upper bypass chamber (43) and the lower bypass chamber (45). The bypass valve seat (20) is inserted into the upper bypass chamber (43). Several third throttling grooves (72) are machined in the inner hole of the bypass valve seat (20). A second radial convex ring (73) is formed between the third throttling grooves (72). The top of the third throttling groove (72) at the upper end is provided with a second valve seat sealing cone surface (71). The flange cover (23) closes the lower opening of the bypass lower cavity (45). A shunting shield (22) is provided in the bypass lower cavity (45). The shunting shield (22) is a cylindrical component. The shunting shield (22) includes an upper thin-walled part (55) and a lower thick-walled part (56). The upper end of the thin-walled part (55) abuts coaxially with the bypass valve seat (20). The lower end of the thick-walled part (56) abuts with the flange cover (23). The outer periphery of the thick-walled part (56) abuts with the bypass lower cavity (45). The sidewall of the thick-walled part (56) is fitted with an annular flow groove (46) on its outer periphery. The inner hole of the thick-walled part (56) is a stepped hole formed by the upper and lower arrangement of the first hole section (58) and the second hole section (59). The diameter of the first hole section (58) is larger than the diameter of the second hole section (59). The first hole section (58) and the second hole section (59) are connected by a rounded corner structure. The bypass valve plug (21) includes a throttling rod section (61), a second thin rod section (62) and a second thick rod section (63) connected from top to bottom. The second thick rod section (63) includes a first cylindrical part (64) and a second cylindrical part (66) arranged vertically. The diameter of the first cylindrical part (64) is larger than the diameter of the second cylindrical part (66). The outer peripheries of the first cylindrical part (64) and the second cylindrical part (66) are connected by a transition conical surface (65). The first cylindrical part (64) and the first hole section (58) are in sliding fit. The second cylindrical part (66) and the second hole section (59) are in sliding fit. A pressure cavity (76) is formed between the rounded corner structure and the transition conical surface (65). Several flow holes (60) connecting the pressure cavity (76) are machined on the bottom surface of the annular flow groove (46). The lower cavity (28) of the main valve body is connected to the annular flow groove (46) through a connecting pipe (17). The throttling rod section (61) slides into the inner hole of the bypass valve seat (20). The top of the throttling rod section (61) is provided with a second valve stem sealing cone surface (69). The second valve seat sealing cone surface (71) and the second valve stem sealing cone surface (69) form the bypass valve port (26). The outer periphery of the second throttling rod section (61) is machined with several fourth throttling grooves (68). A second radial flange (67) is formed between two adjacent fourth throttling grooves (68). The bypass valve plug (21) slides upward, so that the second valve seat sealing cone surface (71) and the second valve stem sealing cone surface (69) are connected. When the surfaces (69) abut and seal, a number of third throttling grooves (72) and a number of fourth throttling grooves (68) are aligned at the same height, and a number of second radial convex rings (73) and a number of second radial flanges (67) are matched one by one. When the bypass valve plug (21) abuts against the flange cover (23), the second valve seat sealing cone surface (71) and the second valve stem sealing cone surface (69) are separated, and a number of third throttling grooves (72) and a number of fourth throttling grooves (68) are staggered in sequence, and a throttling gap is formed between the throttling rod section (61) and the bypass valve seat (20). A working gap is provided between the outer periphery of the thin-walled part (55) and the side wall of the bypass lower cavity (45), and a working gap is provided between the outer periphery of the second thin rod section (62) and the inner periphery of the thin-walled part (55). Several throttling holes (57) are provided on the side wall of the thin-walled part (55), and a permeable first pressure balance hole (70) is provided on the bypass valve plug (21) along the axis.

3. A novel self-regulating recirculation valve according to claim 2, characterized in that: The main valve body assembly (1) includes a lower valve body (33) and an upper valve body (14). The lower cavity (28) of the main valve body is located inside the lower valve body (33). The lower opening of the lower valve body (33) is the medium inlet (27). The top of the lower valve body (33) is provided with a countersunk platform (30). The countersunk platform (30) and the medium inlet (27) are connected through the lower cavity (28) of the main valve body. The lower end face of the upper valve body (14) is provided with a frustoconical cavity (32) that gradually converges from bottom to top. The upper opening of the valve body (14) is the medium outlet (34), which is connected to the frustum cavity (32). The upper valve body (14) and the lower valve body (33) are connected and assembled to form the main valve body assembly (1). The frustum cavity (32) and the countersunk platform (30) are combined to form the upper cavity (29) of the main valve body. The lower valve body (33) has a main valve side port (31) on one side. The bypass outlet pipe (15) passes through the main valve side port (31) and exits the main valve body assembly (1).

4. A novel self-regulating recirculation valve according to claim 3, characterized in that: The bypass valve body (18) is connected to the main valve body assembly (1) through the bypass flange pipe (16), and the inner cavity of the bypass valve body (18) is connected to the bypass outlet pipe (15) through the inner hole of the bypass flange pipe (16).

5. A novel self-regulating recirculation valve according to claim 4, characterized in that: The large valve plug (9) includes a valve plug tray (35) and a valve plug cover (36). The valve plug tray (35) is disc-shaped, and the valve plug cover (36) is annular. The valve plug cover (36) and the valve plug tray (35) are coaxially fitted with a stop. The first thin rod section (50) passes through the valve plug tray (35) and is connected to the limit nut (10). The inner diameter of the second annular protrusion (77) is larger than the outer diameter of the valve plug tray (35). The second annular protrusion (77) is located on the lower end face of the valve plug cover (36).

6. A novel self-regulating recirculation valve according to claim 5, characterized in that: The upper positioning plate (13) and the upper valve body (14) are coaxially fitted with a stop, and the guide sleeve (12) and the upper positioning plate (13) are coaxially fitted with a stop. The guide sleeve (12) is provided with a first tube structure (74) extending downward, and the valve plug cover (36) is provided with a second tube structure (38) extending upward. The inner circumference of the second tube structure (38) is slidably fitted with the outer circumference of the first tube structure (74). The top end of the first tube structure (74) is provided with several second pressure balance holes (75). The upper end of the large spring (11) extends into the first tube structure (74), and the lower end of the large spring (11) abuts against the valve plug tray (35).

7. A novel self-regulating recirculation valve according to any one of claims 1-6, characterized in that: The top of the bypass upper cavity (43) is provided with a bypass pressure sleeve (19), which abuts against the bypass valve seat (20) for a limit.

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