Automatic Recirculation Valve

Abstract

The present invention discloses an automatic recirculation valve, which includes a main valve assembly and a bypass assembly. The bypass assembly includes a bypass valve body, a controller cover, a bypass bushing, a bypass valve stem and a bypass valve core. A fixed pressure reducing flange, a first floating pressure reducing flange and a second floating pressure reducing flange are arranged on the outer periphery of the bypass valve core. A plurality of first pressure reducing holes and a plurality of second pressure reducing holes are respectively arranged on the first floating pressure reducing flange and the second floating pressure reducing flange. A first compression spring and a second compression spring are arranged on the bypass valve core. A sealing valve seat flange, a first valve seat flange and a second valve seat flange are arranged on the inner periphery of the bypass bushing. The distances between the fixed pressure reducing flange and the sealing valve seat flange, between the first floating pressure reducing flange and the first valve seat flange, and between the second floating pressure reducing flange and the second valve seat flange gradually decrease. The present invention can avoid the damage of the valve caused by cavitation, thereby prolonging the service life and safety performance of the valve.

Description

Technical Field

[0001] The present invention relates to the technical field of valves, and particularly to an automatic recirculation valve. Background Art

[0002] The automatic recirculation valve is used to protect centrifugal pumps from damage caused by overheating, severe noise, instability and cavitation under low flow conditions.

[0003] According to the main flow rate, the main valve flap of the automatic recirculation valve will be determined at a certain position. The valve stem of the main line check valve transmits the movement of the main valve flap to the bypass through a lever. The bypass system controls the flow through the bypass and reduces the pressure to the required value at the outlet. When the main valve flap returns to the closed state on the valve seat, all the flow passes through the bypass (reflux). When the main valve flap rises to the top position, the bypass is completely closed, and all the pump flow goes to the process system.

[0004] Since the existing automatic recirculation valve has a poor cavitation prevention effect and the valve is still damaged by cavitation, it is necessary to improve the existing automatic recirculation valve to prevent the generation of cavitation. Summary of the Invention

[0005] The purpose of the present invention is to provide an automatic recirculation valve, which can avoid the damage of the valve caused by cavitation, thereby extending the service life and safety performance of the valve.

[0006] To achieve the above object, the present invention provides the following technical solution: An automatic recirculation valve, comprising a main valve assembly and a bypass assembly. The bypass assembly includes a bypass valve body, a controller cover, a bypass bushing, a bypass valve stem and a bypass valve core. The controller cover and the bypass bushing are installed in the bypass valve body. The bypass valve stem is disposed through the controller cover, and the bypass valve stem is linked with the bypass valve core. Along the axial direction on the outer periphery of the bypass valve core, a fixed pressure reducing flange, a first floating pressure reducing flange and a second floating pressure reducing flange are sequentially arranged. The first floating pressure reducing flange and the second floating pressure reducing flange are slidably arranged on the outer periphery of the bypass valve core. A plurality of first pressure reducing holes and a plurality of second pressure reducing holes are respectively provided on the first floating pressure reducing flange and the second floating pressure reducing flange. And a first compression spring acting on the first floating pressure reducing flange and a second compression spring acting on the second floating pressure reducing flange are provided on the bypass valve core. Along the axial direction on the inner periphery of the bypass bushing, a sealing valve seat flange, a first valve seat flange and a second valve seat flange for respectively forming a sealing fit with the fixed pressure reducing flange, the first floating pressure reducing flange and the second floating pressure reducing flange are provided. The distances between the fixed pressure reducing flange and the sealing valve seat flange, between the first floating pressure reducing flange and the first valve seat flange, and between the second floating pressure reducing flange and the second valve seat flange gradually decrease.

[0007] By adopting the above technical solution, the fixed pressure reducing flange, the sealing valve seat flange, the first floating pressure reducing flange, the first valve seat flange, the second floating pressure reducing flange and the second valve seat flange are arranged alternately. During the closing process of the bypass assembly, since the first floating pressure reducing flange and the second floating pressure reducing flange are floating, the second floating pressure reducing flange first abuts against the second valve seat flange, then the first floating pressure reducing flange abuts against the first valve seat flange, and finally the fixed pressure reducing flange abuts against the sealing valve seat flange to realize the closing of the bypass assembly. This process is a slow closing process, which can linearly reduce the water pressure, effectively prevent the occurrence of cavitation phenomenon, and prevent the sealing pair from being damaged by impact. When the bypass assembly is opened, it is also a slow opening process. A repeatedly bent pressure reducing flow channel is formed between the bypass bushing and the bypass valve core. When the fluid passes through the pressure reducing flow channel, the fluid resistance increases and the energy decreases, playing a multi-stage pressure reducing function, which can avoid the damage of cavitation to the valve, thereby prolonging the service life and safety performance of the valve.

[0008] The present invention is further configured such that an inner sleeve, a middle sleeve and an outer sleeve are sequentially sleeved on the bypass valve core along the axial direction. The fixed pressure reducing flange and the inner sleeve are of an integral structure. A first sliding cavity is provided between the inner sleeve and the middle sleeve, and a second sliding cavity is provided between the middle sleeve and the outer sleeve. The first floating pressure reducing flange is sleeved on the outer peripheries of the inner sleeve and the middle sleeve, and two first sealing rings for respectively forming a sealing fit with the inner sleeve and the middle sleeve are provided on the first floating pressure reducing flange. A first force-receiving flange extending into the first sliding cavity is provided on the first floating pressure reducing flange, and a plurality of first pressure stabilizing through holes communicating with both ends are formed in the first force-receiving flange. The first compression spring is arranged in the first sliding cavity, and one end of the first compression spring abuts against the first force-receiving flange, and the other end of the first compression spring abuts against the inner sleeve. The second floating pressure reducing flange is sleeved on the outer peripheries of the middle sleeve and the outer sleeve, and two second sealing rings for respectively forming a sealing fit with the middle sleeve and the outer sleeve are provided on the second floating pressure reducing flange. A second force-receiving flange extending into the second sliding cavity is provided on the second floating pressure reducing flange, and a plurality of second pressure stabilizing through holes communicating with both ends are formed in the second force-receiving flange. The second compression spring is arranged in the second sliding cavity, and one end of the second compression spring abuts against the second force-receiving flange, and the other end of the second compression spring abuts against the middle sleeve.

[0009] By adopting the above technical solution, the fixed installation of the fixed pressure reducing flange, the sliding installation of the first floating flange and the second floating flange can be realized, and the disassembly and assembly are very convenient, which is beneficial to the pre-assembly and the later maintenance operation.

[0010] The present invention is further configured such that the number of the first pressure reducing holes is the same as the number of the second pressure reducing holes. The orthographic projection of the first pressure reducing holes on the second floating pressure reducing flange does not overlap with the second pressure reducing holes, and the diameter of the first pressure reducing holes is smaller than the diameter of the second pressure reducing holes.

[0011] By adopting the above technical solution, it is possible to further achieve the effect of linear change in water pressure during the opening and closing process of the bypass component.

[0012] The present invention is further configured such that a screw portion is provided at one end of the bypass valve stem close to the bypass valve core, and a screw hole matching the screw portion is formed on the bypass valve core.

[0013] By adopting the above technical solution, it is convenient to realize the quick disassembly and assembly of the bypass valve stem and the bypass valve core, which is beneficial to the pre-assembly and subsequent maintenance and replacement operations.

[0014] The present invention is further configured such that the bypass component further includes a pre-tightening spring. A first spring groove is provided at one end of the bypass valve stem close to the bypass valve core, and a second spring groove is provided at one end of the bypass valve core close to the bypass valve stem. The pre-tightening spring is sleeved on the outer periphery of the screw portion, and both ends of the pre-tightening spring are respectively embedded in the first spring groove and the second spring groove.

[0015] By adopting the above technical solution, the pre-tightening spring can provide a pre-tightening force to the connection structure between the bypass valve stem and the bypass valve core, thereby increasing the friction force between the screw portion of the bypass valve stem and the screw hole of the bypass valve core, and further enhancing the stability of the connection structure between the bypass valve stem and the bypass valve core.

[0016] The present invention is further configured such that the main valve component includes a main valve body, a main valve core, and an eccentric rod. The main valve core is slidably disposed in the main valve body. A main valve seat for abutting against the main valve core and forming a sealing fit is provided in the main valve body. The eccentric rod is hinged to the main valve body, and one end of the eccentric rod abuts against the main valve core, and the other end of the eccentric rod abuts against the bypass valve stem. A sliding cavity is provided in the controller cover, and a first piston portion fitting the inner periphery of the sliding cavity is provided on the bypass valve stem, and a second piston portion fitting the inner periphery of the sliding cavity is provided on the bypass valve core.

[0017] By adopting the above technical solution, the linkage between the main valve core and the bypass valve core can be realized, so that when the main valve component is closed, the bypass component is opened, and when the main valve component is opened, the bypass component is closed.

[0018] The present invention is further configured such that a first support disk and a second support disk are installed in the main valve body. A guide rod is installed on the first support disk. A spring cavity for the guide rod to extend into is provided on the main valve core. A main valve spring is provided in the spring cavity. One end of the main valve spring abuts against the lower end of the guide rod, and the other end of the main valve spring abuts against the lower end of the spring cavity. A guide hole matching the lower end of the main valve core is provided on the second support disk.

[0019] By adopting the above technical solution, the stability of the movement of the main valve core during the opening and closing process can be ensured.

[0020] The present invention is further configured such that a first positioning groove is provided at the lower end of the spring chamber, a second positioning groove is provided at the lower end of the guide rod, and both ends of the main valve spring are respectively embedded in the first positioning groove and the second positioning groove.

[0021] By adopting the above technical solution, the stability of the installation of the main valve spring can be improved, thereby ensuring that it always deforms axially and improving its service life.

[0022] The present invention is further configured such that an internal thread portion is provided on the inner wall of the main valve body corresponding to the position above the main valve seat, and an impact-resistant sleeve is threadedly connected to the internal thread portion.

[0023] By adopting the above technical solution, the medium impact received at the position on the inner wall of the main valve body corresponding to the position above the main valve seat is the strongest at the moment when the main valve assembly is opened, so it is most vulnerable to erosion and cavitation. Therefore, setting the impact-resistant sleeve can protect the main valve body, thereby further improving the service life of the valve.

[0024] The present invention is further configured such that an installation groove is provided in the main valve body, the main valve seat is threadedly connected to the installation groove, a pressure relief assembly is provided on the main valve seat, the pressure relief assembly includes a pressure relief sleeve and a plurality of return springs, an annular guide cavity is provided at one end of the main valve seat close to the installation groove, an annular guide hole is provided at the other end of the main valve seat away from the installation groove, the pressure relief sleeve penetrates through the annular guide hole and extends into the annular guide cavity, a piston flap that forms a sliding fit with the annular guide cavity is provided at the part of the pressure relief sleeve located in the annular guide cavity, a plurality of first circular grooves equivalent in number to the return springs are provided at the lower end of the piston flap, a plurality of second circular grooves equivalent in number to the return springs are provided on the inner end surface of the installation groove, one end of each return spring is embedded in the corresponding first circular groove, the other end of each return spring is embedded in the corresponding second circular groove, an annular groove for the upper end of the pressure relief sleeve to extend into is provided at one end of the main valve spool close to the main valve seat, and a large pressure relief hole group and a small pressure relief hole group are sequentially provided on the pressure relief sleeve in the direction away from the main valve seat.

[0025] By adopting the above technical solution, local pressure relief can be carried out before the main valve assembly is fully opened and fully closed, thereby reducing the water flow impact caused by the pressure difference at the moment of opening and closing, and avoiding the generation of water hammer and cavitation, thereby protecting the valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a schematic structural diagram of the whole of the present invention;

[0027] Figure 2 is Figure 1 an enlarged structural diagram of part A in

[0028] Figure 3 is Figure 1 Schematic enlarged structure diagram of part B in

[0029] Figure 4 is Figure 1 Schematic enlarged structure diagram of part C in

[0030] Figure 5 Schematic structure diagram of the pressure relief sleeve of the present invention.

[0031] In the figure: 1, main valve assembly; 2, bypass assembly; 3, bypass valve body; 4, controller cover; 5, bypass bushing; 6, bypass valve stem; 7, bypass valve core; 8, fixed pressure reducing flange; 9, sealing valve seat flange; 10, pressure reducing flow path; 11, screw part; 12, screw hole; 13, pre-tightening spring; 14, first spring groove; 15, second spring groove; 16, main valve body; 17, main valve core; 18, eccentric rod; 19, main valve seat; 20, sliding cavity; 21, first piston part; 22, second piston part; 23, first support disk; 24, second support disk; 25, guide rod; 26, spring cavity; 27, main valve spring; 28, guide hole; 29, first positioning groove; 30, second positioning groove; 31, internal thread part; 32, impact-resistant sleeve; 33, first floating pressure reducing flange; 34, second floating pressure reducing flange; 35, first pressure reducing hole; 36, second pressure reducing hole; 37, first compression spring; 38, second compression spring; 39, first valve seat flange; 40, second valve seat flange; 41, inner sleeve; 42, middle sleeve; 43, outer sleeve; 44, first sliding cavity; 45, second sliding cavity; 46, first sealing ring; 47, first force-receiving flange; 48, first voltage stabilizing through hole; 49, second sealing ring; 50, second force-receiving flange; 51, second voltage stabilizing through hole; 52, installation groove; 53, pressure relief assembly; 54, pressure relief sleeve; 55, return spring; 56, annular guide cavity; 57, annular guide hole; 58, piston flap; 59, first circular groove; 60, second circular groove; 61, annular groove; 62, large pressure relief hole group; 63, small pressure relief hole group. Specific embodiments

[0032] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0033] Embodiment: As shown in the attached Figures 1 to 5The shown automatic recirculation valve includes a main valve assembly 1 and a bypass assembly 2. The bypass assembly 2 includes a bypass valve body 3, a controller cover 4, a bypass bushing 5, a bypass valve stem 6, and a bypass valve core 7. The controller cover 4 and the bypass bushing 5 are installed inside the bypass valve body 3. The bypass valve stem 6 is disposed through the controller cover 4. The controller cover 4 has a through hole for the medium to pass through, and the bypass valve stem 6 is linked with the bypass valve core 7. Along the axial direction on the outer periphery of the bypass valve core 7, a fixed decompression flange 8, a first floating decompression flange 33, and a second floating decompression flange 34 are sequentially arranged. The cross-sections of the fixed decompression flange 8, the first floating decompression flange 33, and the second floating decompression flange 34 are all in a tapered shape with an inner convex. The first floating decompression flange 33 and the second floating decompression flange 34 are slidably arranged on the outer periphery of the bypass valve core 7. A plurality of first decompression holes 35 and a plurality of second decompression holes 36 are respectively provided on the first floating decompression flange 33 and the second floating decompression flange 34. And a first compression spring 37 acting on the first floating decompression flange 33 and a second compression spring 38 acting on the second floating decompression flange 34 are provided on the bypass valve core 7. Along the axial direction on the inner periphery of the bypass bushing 5, a sealing valve seat flange 9, a first valve seat flange 39, and a second valve seat flange 40 for respectively forming a sealing fit with the fixed decompression flange 8, the first floating decompression flange 33, and the second floating decompression flange 34 are provided. The cross-sections of the sealing valve seat flange 9, the first valve seat flange 39, and the second valve seat flange 40 are all in an arc shape with an inner convex. The distances between the fixed decompression flange 8 and the sealing valve seat flange 9, between the first floating decompression flange 33 and the first valve seat flange 39, and between the second floating decompression flange 34 and the second valve seat flange 40 gradually decrease. The fixed decompression flange 8, the sealing valve seat flange 9, the first floating decompression flange 33, the first valve seat flange 39, the second floating decompression flange 34, and the second valve seat flange 40 are arranged alternately. During the closing process of the bypass assembly 2, since the first floating decompression flange 33 and the second floating decompression flange 34 are floating, the second floating decompression flange 34 first abuts against the second valve seat flange 40, then the first floating decompression flange 33 abuts against the first valve seat flange 39, and finally the fixed decompression flange 8 abuts against the sealing valve seat flange 9 to realize the closing of the bypass assembly 2. This process is a slow closing process, which can make the water pressure decrease linearly, can effectively prevent the generation of cavitation phenomenon, and can prevent the sealing pair from being damaged by impact. When the bypass assembly 2 is opened, it is also a slow opening process. A repeatedly bent decompression flow channel 10 is formed between the bypass bushing 5 and the bypass valve core 7. When the fluid passes through the decompression flow channel 10, the fluid resistance increases and the energy decreases, playing a multi-stage decompression function, which can avoid the damage of cavitation to the valve, thereby prolonging the service life and safety performance of the valve.

[0034] As shown in the appendix Figure 2As shown in the figure, an inner sleeve 41, a middle sleeve 42, and an outer sleeve 43 are sequentially sleeved on the bypass valve core 7 along the axial direction. The inner sleeve 41, the middle sleeve 42, and the outer sleeve 43 can be fixed to the outer periphery of the bypass valve core 7 by screws, and O-rings are clamped between the bypass valve cores 7 respectively. The fixed pressure-reducing flange 8 and the inner sleeve 41 are of an integral structure. A first sliding cavity 44 is provided between the inner sleeve 41 and the middle sleeve 42, and a second sliding cavity 45 is provided between the middle sleeve 42 and the outer sleeve 43. The first floating pressure-reducing flange 33 is sleeved on the outer peripheries of the inner sleeve 41 and the middle sleeve 42, and two first sealing rings 46 for sealing cooperation with the inner sleeve 41 and the middle sleeve 42 respectively are provided on the first floating pressure-reducing flange 33. A first force-bearing flange 47 extending into the first sliding cavity 44 is provided on the first floating pressure-reducing flange 33, and a plurality of first pressure-stabilizing through holes 48 with both ends communicating are provided on the first force-bearing flange 47. The first compression spring 37 is arranged in the first sliding cavity 44, one end of the first compression spring 37 abuts against the first force-bearing flange 47, and the other end of the first compression spring 37 abuts against the inner sleeve 41. The second floating pressure-reducing flange 34 is sleeved on the outer peripheries of the middle sleeve 42 and the outer sleeve 43, and two second sealing rings 49 for sealing cooperation with the middle sleeve 42 and the outer sleeve 43 respectively are provided on the second floating pressure-reducing flange 34. A second force-bearing flange 50 extending into the second sliding cavity 45 is provided on the second floating pressure-reducing flange 34, and a plurality of second pressure-stabilizing through holes 51 with both ends communicating are provided on the second force-bearing flange 50. The second compression spring 38 is arranged in the second sliding cavity 45, one end of the second compression spring 38 abuts against the second force-bearing flange 50, and the other end of the second compression spring 38 abuts against the middle sleeve 42. This design can realize the fixed installation of the fixed pressure-reducing flange 8, the sliding installation of the first floating flange and the second floating flange, and is very convenient for disassembly and assembly, which is beneficial to the preliminary assembly and the subsequent maintenance operation.

[0035] Among them, the number of the first pressure-reducing holes 35 is the same as that of the second pressure-reducing holes 36. The orthographic projection of the first pressure-reducing holes 35 on the second floating pressure-reducing flange 34 does not overlap with the second pressure-reducing holes 36, and the diameter of the first pressure-reducing holes 35 is smaller than that of the second pressure-reducing holes 36. This design can further achieve the effect of linear change of water pressure during the opening and closing process of the bypass assembly 2.

[0036] As shown in the attachment Figure 3 As shown in the figure, a screw portion 11 is provided at one end of the bypass valve stem 6 close to the bypass valve core 7, and a threaded hole 12 matching the screw portion 11 is provided on the bypass valve core 7. This design is convenient for realizing the quick disassembly and assembly of the bypass valve stem 6 and the bypass valve core 7, which is beneficial to the preliminary assembly and the subsequent maintenance and replacement operation. And this design is also convenient for adjusting the overall connection length of the bypass valve stem 6 and the bypass valve core 7, so as to reduce the processing accuracy requirements for the bypass valve body 3 and reduce the processing cost.

[0037] As shown in the attached Figure 3 figure, the bypass assembly 2 further includes a preloading spring 13. One end of the bypass valve stem 6 close to the bypass valve core 7 is provided with a first spring groove 14, and one end of the bypass valve core 7 close to the bypass valve stem 6 is provided with a second spring groove 15. The preloading spring 13 is sleeved on the outer periphery of the screw rod portion 11, and both ends of the preloading spring 13 are respectively embedded in the first spring groove 14 and the second spring groove 15. The preloading spring 13 can provide a preloading force to the connection structure between the bypass valve stem 6 and the bypass valve core 7, thereby increasing the frictional force between the screw rod portion 11 of the bypass valve stem 6 and the threaded hole 12 of the bypass valve core 7, and further enhancing the stability of the connection structure between the bypass valve stem 6 and the bypass valve core 7.

[0038] As shown in the attached Figure 1 and the attached Figure 3 figure, the main valve assembly 1 includes a main valve body 16, a main valve core 17 and an eccentric rod 18. The bypass valve body 3 is installed on the side of the main valve body 16 through bolts, and the inner cavities of the main valve body 16 and the bypass valve body 3 are connected and communicated. The main valve core 17 is slidably arranged in the main valve body 16. A main valve seat 19 for abutting against the main valve core 17 to form a sealing fit is arranged in the main valve body 16. The eccentric rod 18 is hinged to the main valve body 16, and one end of the eccentric rod 18 abuts against the main valve core 17, and the other end of the eccentric rod 18 abuts against the bypass valve stem 6. That is, a through hole with large ends and a small middle is provided on the main valve core 17, and one end of the eccentric rod 18 is inserted into the through hole. When the main valve core 17 slides up and down, the eccentric rod 18 can swing around its hinge point under the drive of the main valve core 17. A sliding cavity 20 is arranged in the controller cover 4. A first piston portion 21 that fits with the inner periphery of the sliding cavity 20 is arranged on the bypass valve stem 6, and a second piston portion 22 that fits with the inner periphery of the sliding cavity 20 is arranged on the bypass valve core 7. Pressure stabilizing holes can be provided on the first piston portion 21 and the second piston portion 22 to ensure the smooth sliding of the first piston portion 21 and the second piston portion 22. This design can realize the linkage between the main valve core 17 and the bypass valve core 7, realize the closing of the main valve assembly 1 and the opening of the bypass assembly 2, and the opening of the main valve assembly 1 and the closing of the bypass assembly 2.

[0039] As shown in the attached Figure 1As shown, a first support disk 23 and a second support disk 24 are installed in the main valve body 16. The two can be installed in the main valve body 16 by interference fit or welded in the main valve body 16. A guide rod 25 is installed on the first support disk 23 by screws. A spring cavity 26 for the guide rod 25 to extend into is provided on the main valve spool 17. A main valve spring 27 is arranged in the spring cavity 26. One end of the main valve spring 27 abuts against the lower end of the guide rod 25, and the other end of the main valve spring 27 abuts against the lower end of the spring cavity 26. A guide hole 28 matching with the lower end of the main valve spool 17 is provided on the second support disk 24. This design can ensure the stability of the movement of the main valve spool 17 during the opening and closing process.

[0040] As shown in the Figure 1 drawing, a first positioning groove 29 is provided at the lower end of the spring cavity 26, and a second positioning groove 30 is provided at the lower end of the guide rod 25. Both ends of the main valve spring 27 are respectively embedded in the first positioning groove 29 and the second positioning groove 30. This design can improve the stability of the installation of the main valve spring 27, so as to ensure that it always deforms axially and improve its service life.

[0041] As shown in the Figure 1 drawing, an internal thread portion 31 is provided on the inner wall of the main valve body 16 corresponding to the position above the main valve seat 19. An impact-resistant sleeve 32 is threadedly connected to the internal thread portion 31. The position on the inner wall of the main valve body 16 corresponding to the position above the main valve seat 19 is subjected to the most intense medium impact at the moment when the main valve assembly 1 is opened, so it is most vulnerable to erosion and cavitation. Therefore, setting the impact-resistant sleeve 32 can protect the main valve body 16 and further improve the service life of the valve.

[0042] As shown in the Figure 4 and the Figure 5As shown, an installation groove 52 is provided in the main valve body 16. The main valve seat 19 is threadedly connected to the installation groove 52, and a sealing gasket is clamped between the main valve seat 19 and the installation groove 52. A pressure relief assembly 53 is provided on the main valve seat 19. The pressure relief assembly 53 includes a pressure relief sleeve 54 and a plurality of return springs 55. One end of the main valve seat 19 close to the installation groove 52 is provided with an annular guiding cavity 56, and the other end of the main valve seat 19 away from the installation groove 52 is provided with an annular guiding hole 57. The pressure relief sleeve 54 penetrates through the annular guiding hole 57 and extends into the annular guiding cavity 56. A piston flap 58 that forms a sliding fit with the annular guiding cavity 56 is provided at the part of the pressure relief sleeve 54 located in the annular guiding cavity 56. A plurality of first circular grooves 59 equivalent in number to the return springs 55 are formed at the lower end of the piston flap 58. A plurality of second circular grooves 60 equivalent in number to the return springs 55 are formed on the inner end surface of the installation groove 52. One end of each return spring 55 is embedded in the corresponding first circular groove 59, and the other end of each return spring 55 is embedded in the corresponding second circular groove 60. An annular groove 61 for the upper end of the pressure relief sleeve 54 to extend into is provided at one end of the main valve spool 17 close to the main valve seat 19. A large pressure relief hole group 62 and a small pressure relief hole group 63 are sequentially provided on the pressure relief sleeve 54 in the direction away from the main valve seat 19. The large pressure relief hole group 62 and the small pressure relief hole group 63 are respectively a plurality of large pressure relief holes and a plurality of small pressure relief holes, and the diameter of the large pressure relief holes is larger than that of the small pressure relief holes. This design can perform partial pressure relief before the main valve assembly 1 is fully opened and fully closed, thereby reducing the water flow impact caused by the pressure difference at the moment of opening and closing, and can avoid the generation of water hammer and cavitation, thus achieving the effect of protecting the valve.

Claims

1. Automatic recirculation valve, comprising a main valve assembly (1) and a bypass assembly (2), wherein the bypass assembly (2) includes a bypass valve body (3), a controller cover (4), a bypass bushing (5), a bypass valve stem (6) and a bypass valve core (7). The controller cover (4) and the bypass bushing (5) are installed in the bypass valve body (3). The bypass valve stem (6) is disposed through the controller cover (4), and the bypass valve stem (6) is linked with the bypass valve core (7). Characterized in that: On the outer periphery of the bypass valve core (7), a fixed pressure reducing flange (8), a first floating pressure reducing flange (33) and a second floating pressure reducing flange (34) are sequentially arranged along the axial direction. The first floating pressure reducing flange (33) and the second floating pressure reducing flange (34) are slidably arranged on the outer periphery of the bypass valve core (7). A plurality of first pressure reducing holes (35) and a plurality of second pressure reducing holes (36) are respectively provided on the first floating pressure reducing flange (33) and the second floating pressure reducing flange (34). And a first compression spring (37) acting on the first floating pressure reducing flange (33) and a second compression spring (38) acting on the second floating pressure reducing flange (34) are provided on the bypass valve core (7). On the inner periphery of the bypass bushing (5), a sealing valve seat flange (9), a first valve seat flange (39) and a second valve seat flange (40) are respectively provided for sealing cooperation with the fixed pressure reducing flange (8), the first floating pressure reducing flange (33) and the second floating pressure reducing flange (34). The distance between the fixed pressure reducing flange (8) and the sealing valve seat flange (9), the distance between the first floating pressure reducing flange (33) and the first valve seat flange (39), and the distance between the second floating pressure reducing flange (34) and the second valve seat flange (40) gradually decrease.

2. The automatic recirculation valve according to claim 1, Characterized in that: An inner sleeve (41), a middle sleeve (42) and an outer sleeve (43) are sequentially sleeved on the bypass valve core (7) along the axial direction. The fixed pressure reducing flange (8) and the inner sleeve (41) are of an integral structure. A first sliding cavity (44) is provided between the inner sleeve (41) and the middle sleeve (42), and a second sliding cavity (45) is provided between the middle sleeve (42) and the outer sleeve (43). The first floating pressure reducing flange (33) is sleeved on the outer circumferences of the inner sleeve (41) and the middle sleeve (42), and two first sealing rings (46) for respectively forming a sealing fit with the inner sleeve (41) and the middle sleeve (42) are provided on the first floating pressure reducing flange (33). A first force-bearing flange (47) extending into the first sliding cavity (44) is provided on the first floating pressure reducing flange (33). A plurality of first pressure stabilizing through holes (48) with both ends communicating are formed in the first force-bearing flange (47). The first compression spring (37) is arranged in the first sliding cavity (44), one end of the first compression spring (37) abuts against the first force-bearing flange (47), and the other end of the first compression spring (37) abuts against the inner sleeve (41). The second floating pressure reducing flange (34) is sleeved on the outer circumferences of the middle sleeve (42) and the outer sleeve (43), and two second sealing rings (49) for respectively forming a sealing fit with the middle sleeve (42) and the outer sleeve (43) are provided on the second floating pressure reducing flange (34). A second force-bearing flange (50) extending into the second sliding cavity (45) is provided on the second floating pressure reducing flange (34). A plurality of second pressure stabilizing through holes (51) with both ends communicating are formed in the second force-bearing flange (50). The second compression spring (38) is arranged in the second sliding cavity (45), one end of the second compression spring (38) abuts against the second force-bearing flange (50), and the other end of the second compression spring (38) abuts against the middle sleeve (42).

3. The automatic recirculation valve according to claim 2, characterized in that: the number of the first pressure reducing holes (35) is the same as that of the second pressure reducing holes (36). The orthographic projection of the first pressure reducing holes (35) on the second floating pressure reducing flange (34) does not overlap with the second pressure reducing holes (36), and the diameter of the first pressure reducing holes (35) is smaller than that of the second pressure reducing holes (36).

4. The automatic recirculation valve according to claim 1, characterized in that: a screw rod portion (11) is provided at one end of the bypass valve stem (6) close to the bypass valve core (7), and a screw hole (12) matching with the screw rod portion (11) is formed in the bypass valve core (7).

5. The automatic recirculation valve according to claim 4, characterized in that: The bypass assembly (2) further includes a preloading spring (13). One end of the bypass valve stem (6) close to the bypass valve core (7) is provided with a first spring groove (14), and one end of the bypass valve core (7) close to the bypass valve stem (6) is provided with a second spring groove (15). The preloading spring (13) is sleeved on the outer periphery of the screw rod portion (11), and both ends of the preloading spring (13) are respectively embedded in the first spring groove (14) and the second spring groove (15).

6. The automatic recirculation valve according to claim 1, characterized in that: The main valve assembly (1) includes a main valve body (16), a main valve core (17) and an eccentric rod (18). The main valve core (17) is slidably arranged in the main valve body (16). A main valve seat (19) for abutting against the main valve core (17) and forming a sealing fit is arranged in the main valve body (16). The eccentric rod (18) is hinged to the main valve body (16), one end of the eccentric rod (18) abuts against the main valve core (17), and the other end of the eccentric rod (18) abuts against the bypass valve stem (6); A sliding cavity (20) is arranged in the controller cover (4), and a first piston portion (21) that fits with the inner periphery of the sliding cavity (20) is arranged on the bypass valve stem (6), and a second piston portion (22) that fits with the inner periphery of the sliding cavity (20) is arranged on the bypass valve core (7).

7. The automatic recirculation valve according to claim 6, characterized in that: A first support disc (23) and a second support disc (24) are installed in the main valve body (16). A guide rod (25) is installed on the first support disc (23). A spring cavity (26) for the guide rod (25) to extend into is arranged on the main valve core (17). A main valve spring (27) is arranged in the spring cavity (26). One end of the main valve spring (27) abuts against the lower end of the guide rod (25), and the other end of the main valve spring (27) abuts against the lower end of the spring cavity (26). A guide hole (28) that cooperates with the lower end of the main valve core (17) is arranged on the second support disc (24).

8. The automatic recirculation valve according to claim 7, characterized in that: A first positioning groove (29) is arranged at the lower end of the spring cavity (26), a second positioning groove (30) is arranged at the lower end of the guide rod (25), and both ends of the main valve spring (27) are respectively embedded in the first positioning groove (29) and the second positioning groove (30).

9. The automatic recirculation valve according to claim 6, characterized in that: An internal thread portion (31) is arranged on the inner wall of the main valve body (16) corresponding to the position above the main valve seat (19), and an impact-resistant sleeve (32) is threadedly connected to the internal thread portion (31).

10. The automatic recirculation valve according to claim 6, characterized in that: An installation groove (52) is provided in the main valve body (16). The main valve seat (19) is threadedly connected to the installation groove (52). A pressure relief assembly (53) is provided on the main valve seat (19). The pressure relief assembly (53) includes a pressure relief sleeve (54) and a plurality of return springs (55). An annular guiding cavity (56) is provided at one end of the main valve seat (19) close to the installation groove (52). An annular guiding hole (57) is provided at one end of the main valve seat (19) away from the installation groove (52). The pressure relief sleeve (54) penetrates through the annular guiding hole (57) and extends into the annular guiding cavity (56). A piston flap (58) that forms a sliding fit with the annular guiding cavity (56) is provided at the part of the pressure relief sleeve (54) located in the annular guiding cavity (56). A plurality of first circular grooves (59) with a number corresponding to that of the return springs (55) are formed at the lower end of the piston flap (58). A plurality of second circular grooves (60) with a number corresponding to that of the return springs (55) are formed on the inner end surface of the installation groove (52). One end of each return spring (55) is embedded in the corresponding first circular groove (59), and the other end of each return spring (55) is embedded in the corresponding second circular groove (60). An annular groove (61) for the upper end of the pressure relief sleeve (54) to extend into is provided at one end of the main valve spool (17) close to the main valve seat (19). The pressure relief sleeve (54) is sequentially provided with a large pressure relief hole group (62) and a small pressure relief hole group (63) in the direction away from the main valve seat (19).

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