Double-seat regulating valve

Abstract

The invention discloses a double-seat adjusting valve which comprises a valve body. A valve front flow channel, a valve cavity and a valve rear flow channel are arranged in the valve body. A lower valve seat matched with the lower valve element is arranged on the lower side of the valve cavity, and an upper valve seat matched with the upper valve element is arranged on the upper side of the valve cavity. And the throttling diameter of the lower valve seat at the lower valve seat is 0.50-0.90 times of the nominal drift diameter. Aiming at the structural particularity of the double-seat regulating valve, the design thought insisting in the industry for a long time is changed subversively, the structural size of the formed valve is reduced favorably, and the throttling structural form of the sleeve regulating valve is integrated, so that the technical purposes of reducing forming materials, reducing forming weight, resisting cavitation, resisting scouring and reducing flowing noise are achieved, and the service life of the double-seat regulating valve is prolonged. And the cost performance is improved.

Description

Technical Field

[0001] This invention relates to control valves, specifically a double-seat control valve. Background Technology

[0002] Control valves for fluid media process control can be classified into single-seat control valves, sleeve control valves, double-seat control valves, etc., depending on the type of sealing structure inside the valve.

[0003] Among them, the double-seat regulating valve refers to a valve body with two valve seats and two valve cores that cooperate with them in the valve cavity. The valve cores form an upper and lower double guide arrangement structure in the valve body (the upper guide structure is the valve cover, and the lower guide structure is the bottom cover).

[0004] The technical advantages of a double-seat control valve are: because the fluid pressure acts on the upper and lower valve cores, the unbalanced forces basically cancel each other out, achieving a basic balance of forces, thus allowing for a larger operating pressure difference.

[0005] The technical disadvantages of dual-seat control valves are: - Due to machining errors, when closed, the upper and lower valve cores cannot reliably seal with their corresponding valve seats at the same time, resulting in a significantly greater leakage than that of a single-seat regulating valve. - The valve core is located at the double guide point in the valve body, especially the guide structure at the bottom cover, which is easily stuck by solid particles. It is not suitable for process control of fluid media with high viscosity, suspension, or solid particle sediment. - To accommodate the arrangement of upper and lower dual valve cores, and due to unreasonable design, the valve body, including the valve cavity and the downstream flow channel, has a large arrangement space. This results in the overall structure of the dual-seat control valve being too large, requiring too much molding material, being too heavy, having high manufacturing costs, and having a low cost-performance ratio, making it difficult for the market to accept.

[0006] For a long time, the industry has designed double-seat control valves by having the lower valve seat's throttling diameter basically equal to the nominal diameter (i.e., dg1=DN), and the upper valve seat's throttling diameter (dg1) 2mm larger than the lower valve seat's throttling diameter (dg1) (i.e., dg1+2mm). However, after decades of repeated research on existing double-seat control valves, the inventors have discovered that the current design has technical drawbacks because: - Approximately 50% of the fluid medium flows into the lower valve seat and the upper valve seat respectively through the pre-valve flow channel; Since the throttling diameter at the lower valve seat is approximately equal to the nominal diameter, the flow velocity of the fluid medium flowing through the lower valve seat will decrease by about half compared to the flow velocity flowing through the upstream flow channel. The same applies to the upper valve seat. More specifically, the throttling diameter dg at both the upper and lower valve seats is approximately equal to the nominal diameter DN, while the flow rate of the fluid medium is reduced by about 50%. In other words, the excessively large flow area at the upper and lower valve seats causes the fluid medium to flow at a reduced speed when entering the corresponding valve seat. However, according to the operating characteristics of the control valve, the fluid medium should flow at an accelerated speed when entering the corresponding valve seat. Therefore, to meet this characteristic, a valve core with a relatively large structural volume is required to create a large throttling orifice by blocking the flow over a large area. - Obviously, the larger flow structure at the upper and lower valve seats will result in a larger valve body structure volume.

[0007] A search and analysis of publicly available Chinese patent documents revealed that although various types of double-seat control valves with different structures have been disclosed, such as the patents titled "A Special High-Temperature Balance Cage Control Valve" (Publication No. CN213929681 U, Publication Date August 10, 2021), "Double-Seat Cage Control Valve" (Publication No. CN 205639639 U, Publication Date October 12, 2016), and "A Quick-Change Double-Seat Control Valve with Sealing Compensation and Anti-Rotation Functions" (Publication No. CN214662119 U, Publication Date November 9, 2021), these double-seat control valves all aim at noise reduction. To date, no technology has been disclosed that reduces the structural volume of the double-seat control valve by altering the fit between the throttling diameter and the nominal diameter of the valve seat. Summary of the Invention

[0008] The technical objective of this invention is to provide a double-seat regulating valve that is advantageous in reducing structural volume, addressing the structural uniqueness of the traditional double-seat regulating valve and the shortcomings of the prior art.

[0009] The technical solution adopted by the present invention to achieve its technical objective is: a double-seat regulating valve, including a valve body; The valve body has a front flow channel, a valve cavity, and a rear flow channel; The lower side of the valve cavity is provided with a lower valve seat that cooperates with the lower valve core, and the upper side is provided with an upper valve seat that cooperates with the upper valve core. The throttling diameter of the lower valve seat at the lower valve seat is 0.50 to 0.90 times the nominal diameter.

[0010] Furthermore, the throttling diameter of the lower valve seat at the lower valve seat is 0.60 to 0.80 times the nominal diameter; The throttling diameter of the upper valve seat is 0.5 to 10 mm larger than that of the lower valve seat.

[0011] The aforementioned technical measures, tailored to the unique structural characteristics of double-seat control valves, fundamentally alter the industry's long-standing design principle that the lower valve seat's throttling diameter should be roughly equal to the nominal diameter. Instead, the throttling diameter of the lower valve seat is designed to be 0.50 to 0.90 times the nominal diameter (especially when choosing 0.60 to 0.80 times). This design, while ensuring sufficient diversion of the fluid medium from the upstream flow channel, allows the flow area at the lower valve seat to be essentially matched to the flow rate of the fluid medium passing through it (the same applies to the upper valve seat), thus reducing the structural dimensions of the lower valve seat. This enables a smaller, more compact internal structure of the valve body, thereby reducing the overall volume of the molded valve. This achieves the technical objectives of reducing molding material usage, lowering molding weight, and improving cost-effectiveness, resulting in significant economic benefits and facilitating market promotion and application.

[0012] The design concept of the above technical measures is based on the assumption that the flow rate of the fluid medium flowing into the upstream channel is unit 1, and according to fluid conservation, the flow rate of the fluid medium flowing out of the downstream channel is also unit 1. Since the flow rates of the fluid medium entering the lower valve seat and the upper valve seat are each approximately 50%, if the velocity of the approximately 50% flow rate of the fluid medium flowing through the lower and upper valve seats is to be basically consistent with the velocity of the DN channel at the inlet of the upstream channel, then the flow area of ​​the lower and upper valve seats should be half of the DN flow area, i.e., π / 4 * dg1. 2 =0.5*π / 4DN 2 Therefore, we can obtain dg1 = 0.707DN (approximately).

[0013] If the flow velocity of the medium before entering the high-speed throttling is appropriately increased, so that the medium gradually accelerates before throttling to reduce the resistance of sudden acceleration, then the throttling diameter of the lower valve seat can be further designed to be dg1=0.65DN.

[0014] Taking DN100 as an example, the traditional design uses dg1=100 and dg2=102. If designed with dg1=0.65DN, then dg1=65 and dg2=67. This allows the throttling diameter of the double-seat control valve to be reduced by two stops (one stop for dg100 is dg80; two stops is dg65), resulting in a more compact valve body and associated internal components. This significantly reduces the overall valve weight, as well as the size and thrust of the actuator, leading to a substantial decrease in manufacturing costs and a significantly improved price-performance ratio, thus enhancing market competitiveness.

[0015] As one of the preferred solutions, a lower sleeve is provided inside the valve cavity of the valve body to accommodate the lifting and lowering stroke range of the lower valve core; A lower throttling window is provided at the lower circumference of the lower sleeve; A fluid passage is provided at the upper circumference of the lower sleeve, located below the upper valve seat; An upper sleeve is provided above the valve cavity of the valve body to accommodate the lifting stroke range of the upper valve core; An upper throttling window is provided at the lower circumference of the upper sleeve.

[0016] The above-mentioned technical measures, based on the traditional double-seat control valve structure, innovatively introduce a throttling structure of a sleeve control valve, and have the following main technical advantages: 1. After being throttled by the throttling windows of the upper and lower sleeves, a "multi-flow stream" is formed (generally, there are 4 to 8 throttling windows in the upper / lower sleeves, totaling 8 to 16) flow. The throttling area is concentrated on the windows of the sleeve (rather than the circumferential throttling of the traditional plunger-type valve core and seat), which makes the throttling area more concentrated and helps to reduce flow noise and flow erosion. 2. After being throttled through the throttling windows of the upper and lower sleeves, a "multi-stream" flow is formed, which enables the fluid medium to consume a large amount of high pressure differential energy during the throttling process and during the friction and collision process of the confluence. This is beneficial to improving the technical effects of cavitation resistance, erosion resistance, and noise reduction, and can reliably adapt to the harsh working environment of high temperature, high pressure, and large pressure differential. 3. It facilitates the reliable assembly of the upper and lower sleeves within the valve body through a clamping structure, eliminating the traditional threaded connection structure of the valve seat within the valve body.

[0017] Furthermore, the lower sleeve and the upper sleeve are separate structures, and the inner diameter of the lower sleeve is smaller than the inner diameter of the upper sleeve; The top end of the lower sleeve and the bottom end of the upper sleeve are joined together at the top of the valve cavity. The bottom inner wall of the lower sleeve has a radially protruding structure forming a lower valve seat that matches the lower valve core; At the top of the lower sleeve and at the bottom of the upper sleeve, a radially protruding structure forms an upper valve seat that mates with the upper valve core.

[0018] Furthermore, the lower sleeve and the upper sleeve are formed from seamless steel pipes.

[0019] The aforementioned technical measures simplify the forming structure of the upper and lower sleeves, facilitate processing, and are particularly beneficial for forming using seamless steel pipes. The upper and lower sleeves formed from seamless steel pipes exhibit stable and reliable structural quality. This reliability also allows for thinner walls in the upper and lower sleeves, reducing structural volume and contributing to the miniaturization of the entire valve structure.

[0020] Alternatively, the lower sleeve and the upper sleeve are integrally formed, the inner diameter of the lower sleeve is smaller than the inner diameter of the upper sleeve, and the lower sleeve is fitted with the upper sleeve at the bottom of the upper sleeve in a coaxial stepped structure. The bottom inner wall of the lower sleeve has a radially protruding structure forming a lower valve seat that matches the lower valve core; At the top of the lower sleeve and at the bottom of the upper sleeve, a radially protruding structure forms an upper valve seat that mates with the upper valve core.

[0021] The above-mentioned technical measures, as an alternative, can simplify the assembly structure of the sleeve in the valve body and improve the sealing performance of the sleeve assembly in the valve body.

[0022] Furthermore, the valve body is a three-way structure with an opening at the connection between the valve front flow channel, the valve rear flow channel, and the valve cover; The lower valve core and the upper valve core are guided by the mounting structure at the valve cover and the assembly structure in the corresponding sleeve for their lifting stroke.

[0023] Furthermore, the downstream flow channel has a second downstream branch flow channel that serves as a connection to the lower side of the valve chamber; The outline of the second branch channel after the valve on the valve body is formed by a smooth curve without sharp angles from front to back.

[0024] The above-mentioned technical measures have changed the traditional double-guide structure of the upper and lower positions inside the valve of the double-seat control valve, and have the following main technical advantages: 1. The valve body has a three-way structure, which requires one less channel to process than the traditional four-way structure (the traditional structure has a bottom cover connection point directly below the valve cover connection point), simplifying the processing flow and reducing processing costs; 2. There is no need to machine a channel opening at the bottom of the valve body, and therefore no need to consider the connection structure of the bottom cover. This eliminates the need to make the bottom of the valve body "thick" during molding, which allows the bottom of the valve body to be molded with "thin walls" (provided that the structural strength is the premise), reducing the amount of molding material and the weight of molding, and lowering the molding cost. 3. The bottom cover connection structure at the bottom of the valve body has been eliminated, which eliminates a potential source of leakage and helps improve the sealing reliability of the formed valve body; 4. The valve core does not need to form a guide assembly structure at the bottom of the valve body, which helps to reduce the obstruction of the valve core guide structure by solid particles, especially settling solid particles, thereby improving the stability of the valve in service. 5. The fluid medium flowing out of the lower valve seat can flow smoothly with low resistance in the streamlined downstream branch channel 2 at the bottom of the valve body, resulting in good flow performance.

[0025] Furthermore, the lower valve core has a flat structure in the height direction, and the bottom outer periphery of the lower valve core is formed with a beveled structure to form a lower core side sealing surface that matches the lower valve seat.

[0026] Furthermore, the upper valve core has a flat structure in the height direction, and the bottom outer periphery of the upper valve core is formed with an upper core side sealing surface that matches the upper valve seat in a beveled structure.

[0027] The aforementioned flattened structure of the upper and lower valve cores significantly reduces the material used for valve core molding and facilitates processing and molding; secondly, it reduces the weight of the valve core, which helps control the overall molding weight of the valve; and thirdly, it reduces the structural volume of the valve core, which helps control the overall structural volume of the valve.

[0028] As one of the preferred embodiments, the outer tail of the valve cavity has a flat guide nozzle that extends horizontally into the flow channel after the valve. The outer upper wall of the valve cavity and the top side of the guide nozzle are smoothly transitioned in a streamlined manner with an included angle of 120 to 160°. The lower outer wall of the valve cavity and the bottom side of the guide nozzle have a smooth, streamlined transition at an angle of 120° to 160°.

[0029] Furthermore, the guide nozzle is located at the center of the downstream flow channel, and the top profile structure of the guide nozzle—that is, the bottom profile structure of the downstream branch channel one—is symmetrically formed with the bottom profile structure of the guide nozzle—that is, the top profile structure of the downstream branch channel two.

[0030] The aforementioned guide nozzle structure allows the fluid media flowing out of the first and second downstream branch channels to merge smoothly and steadily, reducing energy loss caused by mutual impact and collision between the two fluid streams during merging, thereby helping to reduce eddies and improve flow capacity.

[0031] The beneficial technical effects of the present invention are as follows: the above-mentioned technical measures, in view of the special structure of the double-seat regulating valve, have revolutionized the design concept that has been adhered to in the industry for a long time. On the one hand, it is conducive to reducing the structural volume of the molded valve, so as to reduce the molding material, reduce the molding weight, and improve the cost performance. On the other hand, it is conducive to reducing flow noise and erosion resistance. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of one structure of the present invention.

[0033] Figure 2 This is another structural schematic diagram of the present invention.

[0034] Figure 3 for Figure 2 A magnified view of the part where the lower sleeve mates with the lower valve core.

[0035] Figure 4 for Figure 2 A magnified view of the part where the upper sleeve mates with the upper valve core.

[0036] Figure 5 for Figure 2 A magnified view of a portion of the flow guide nozzle.

[0037] Figure 6 This is another structural schematic diagram of the present invention.

[0038] The symbols in the diagram have the following meanings: 1—Valve body; 11—Flow channel before valve; 12—Flow channel after valve; 121—Branch channel one after valve; 122—Branch channel two after valve; 13—Valve cavity; 131—Outer upper wall; 132—Outer lower wall; 14—Guide nozzle; 141—Top side of guide nozzle; 142—Bottom side of guide nozzle; 2—Lower sleeve; 21—Lower throttling window; 22—Fluid passage; 2′—Lower valve seat; 3—Upper sleeve; 31—Upper throttling window; 3′—Upper valve seat; 4—Lower valve core; 41—Lower core side sealing surface; 42—Lower core side bottom surface; 5—Upper valve core; 51—Upper core side sealing surface; 52—Upper core side bottom surface; 6—Valve stem; 7—Valve cover; 8—Bottom cover; DN—Nominal diameter; dg1—Lower valve seat throttling diameter; dg2—Upper valve seat throttling diameter. Detailed Implementation

[0039] This invention relates to control valves, specifically a double-seat control valve. The technical content of this invention will be described in detail below with several embodiments, wherein Embodiment 1 is illustrated in conjunction with the accompanying drawings. Figure 1 The technical solution of the present invention will be clearly and thoroughly explained; Embodiment 2 is illustrated in conjunction with the accompanying drawings. Figure 2 , Figure 3 , Figure 4 and Figure 5 The technical solution of the present invention will be clearly and thoroughly explained; Embodiment 3 is illustrated in conjunction with the accompanying drawings. Figure 6 The technical solution of the present invention will be clearly and thoroughly explained; although other embodiments are not shown in separate drawings, their main structures can still be referred to the drawings of Embodiments 1, 2 and 3.

[0040] It should be noted that the accompanying drawings of this invention are schematic, and unnecessary details have been simplified in order to clarify the technical objectives of this invention, so as to avoid obscuring the technical solutions contributed by this invention to the prior art.

[0041] Example 1 See Figure 1 As shown, the dual-seat regulating valve of the present invention includes a valve body 1, which has a front flow channel 11, a valve cavity 13 and a rear flow channel 12.

[0042] On the lower side of the valve cavity 13, a lower valve seat 2' that mates with the lower valve core 4 is provided by a threaded connection structure. On the upper side of the valve cavity 13, an upper valve seat 3' that mates with the upper valve core 5 is provided by a threaded connection structure.

[0043] The upper valve core 5 and lower valve core 4 are coaxially connected to the valve stem 6, and mate with the corresponding upper valve seat 3' and lower valve seat 2' on the upper and lower sides of the valve cavity 13. The upper end of the valve stem 6 is guided through the valve cover 7 connected to the upper part of the valve body 1 and serves as a connection to the actuator. The lower end of the valve stem 6 is connected to the bottom cover 8 connected to the bottom of the valve body 1 via a guide structure.

[0044] The throttling diameter dg1 of the lower valve seat at the aforementioned lower valve seat 2′ is approximately 0.80 times the nominal diameter DN.

[0045] The throttling diameter dg2 of the upper valve seat at the aforementioned upper valve seat 3′ is approximately 8 mm larger than the throttling diameter dg1 of the aforementioned lower valve seat, i.e., dg2 = dg1 + 8 mm.

[0046] The fluid medium entering through the inlet channel 11 flows in two directions at the upper valve seat 3′ on the upper side and the lower valve seat 2′ on the lower side of the valve cavity 13. After the flow is split, it passes over the outer wall of the valve cavity 13 and finally converges at the outlet channel 12.

[0047] At the outer tail of the valve cavity 13, there is a flat guide nozzle 14 extending horizontally into the valve downstream flow channel 12. The guide nozzle 14 is basically located at the center of the valve downstream flow channel 12, thereby branching the valve downstream flow channel 12 into a valve downstream branch channel 121 connecting the upper valve seat 3' and a valve downstream branch channel 122 connecting the lower valve seat 2'.

[0048] The outer upper wall 131 of the valve cavity 13 (the area adjacent to the guide nozzle 14) and the top guide side 141 of the guide nozzle 14 form a smooth, streamlined transition at an angle of approximately 120°. This facilitates smooth flow of the fluid medium at the guide nozzle 14 and minimizes impact with the fluid medium below. Similarly, the outer lower wall 132 of the valve cavity 13 (the area adjacent to the guide nozzle 14) and the bottom guide side 142 of the guide nozzle 14 also form a smooth, streamlined transition at an angle of approximately 120°. Thus, the top and bottom guide side contours of the guide nozzle 14 are essentially symmetrically formed.

[0049] Example 2 See Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, the dual-seat regulating valve of the present invention includes a valve body 1, which has a front flow channel 11, a valve cavity 13 and a rear flow channel 12.

[0050] The valve body 1 is a three-way structure with an opening at the connection between the valve front flow channel 11, the valve rear flow channel 12 and the valve cover 7. The bottom of the valve body 1 is an integral structure without openings.

[0051] At the top of the valve cavity 13, an upper valve seat is formed by the mating structure of the upper sleeve 3 and the lower sleeve 2. At the bottom of the valve cavity 13, a lower valve seat is formed by the lower sleeve 2.

[0052] Specifically, within the valve cavity 13 of the valve body 1, a lower sleeve 2 is provided to accommodate the lifting and lowering stroke range of the lower valve core 4, within the overlapping structure between the upper and lower sleeves and the pressing structure of the valve cover 7 against the upper sleeve 3. Above the valve cavity 13 of the valve body 1, an upper sleeve 3 is provided to accommodate the lifting and lowering stroke range of the upper valve core 5.

[0053] The lower sleeve 2 and the upper sleeve 3 are separate structures, with the inner diameter of the lower sleeve 2 being smaller than that of the upper sleeve 3. The top end of the lower sleeve 2 and the bottom end of the upper sleeve 3 are joined together at the top of the valve cavity 13 using an interlocking stop. The outer edge of the bottom end of the upper sleeve 3 rests on the top of the valve cavity 13 via a sealing gasket.

[0054] At the bottom inner wall of the lower sleeve 2, a radially protruding structure forms a lower valve seat that mates with the lower valve core 4. The throttling diameter dg1 of the lower valve seat is approximately 0.65 times the nominal diameter DN.

[0055] At the top of the lower sleeve 2, a radially protruding structure forms an upper valve seat that mates with the upper valve core 5 at the bottom of the upper sleeve 3. The throttling diameter dg2 of the upper valve seat is approximately 5mm larger than the throttling diameter dg1 of the lower valve seat, i.e., dg2 = dg1 + 5mm.

[0056] Six lower throttling windows 21 are evenly distributed around the lower circumference of the lower sleeve 2.

[0057] Six fluid passages 22 are evenly distributed around the upper circumference of the lower sleeve 2, located below the upper valve seat. The total flow area of ​​the fluid passages 22 is greater than the total flow area of ​​the lower throttling window 21.

[0058] Six upper throttling windows 31 are evenly distributed around the lower circumference of the upper sleeve 3.

[0059] The lower sleeve 2 and the upper sleeve 3 are respectively machined from seamless steel pipes.

[0060] The upper valve core 5 and lower valve core 4, coaxially connected to the valve stem 6, mate with the corresponding upper sleeve 3 and lower sleeve 2 on the upper and lower sides of the valve cavity 13. The upper end of the valve stem 6 is guided through the valve cover 7 connected to the upper part of the valve body 1, serving as a connection to the actuator. Simultaneously, the assembly structure of the upper and lower valve cores within the corresponding sleeves also forms a guiding fit structure, compensating for the lack of a guiding structure at the lower end of the valve stem 6. In other words, the lower valve core 4 and upper valve core 5 are guided during their lifting stroke through the through-mounting structure at the valve cover 7 and the assembly structure within the corresponding sleeves.

[0061] The lower valve core 4 has a flat structure in the height direction. The bottom outer periphery of the lower valve core 4 is formed with a beveled structure to form a lower core side sealing surface 41 that matches the lower valve seat. The bottom edge of the lower core side sealing surface 41 forms a lower core side bottom surface 42 that is basically planar.

[0062] The upper valve core 5 has a flat structure in the height direction. The bottom outer periphery of the upper valve core 5 is formed with an upper core side sealing surface 51 that matches the upper valve seat in a sloping structure. The bottom edge of the upper core side sealing surface 51 forms an upper core side bottom surface 52 that is basically planar.

[0063] The fluid medium entering through the inlet channel 11 flows upward and downward through the lower throttling window 21 of the lower sleeve 2 and the fluid channel 22 of the lower sleeve 2 in the valve cavity 13. After the flow is split, it passes over the outer wall of the valve cavity 13 and finally converges at the outlet channel 12.

[0064] At the outer tail of the valve cavity 13, there is a flat guide nozzle 14 extending horizontally into the valve downstream flow channel 12. The guide nozzle 14 is basically located at the center of the valve downstream flow channel 12, thereby branching the valve downstream flow channel 12 into a valve downstream branch channel 121 connecting the upper sleeve 3 and a valve downstream branch channel 122 connecting the lower sleeve 2.

[0065] The outer upper wall 131 of the valve cavity 13 (the area adjacent to the guide nozzle 14) and the top guide side 141 of the guide nozzle 14 form a smooth, streamlined transition at an angle of approximately 150°. This facilitates the smooth flow of the fluid medium at the guide nozzle 14 and minimizes the impact with the fluid medium below. Similarly, the outer lower wall 132 of the valve cavity 13 (the area adjacent to the guide nozzle 14) and the bottom guide side 142 of the guide nozzle 14 also form a smooth, streamlined transition at an angle of approximately 150°. Thus, the top and bottom guide side contours of the guide nozzle 14 are essentially symmetrically formed.

[0066] The outline of the downstream branch channel 2 122 on the valve body 1 is formed by a smooth curve without sharp angles from front (upstream) to back (downstream). That is, the outline of the downstream branch channel 2 122 on the valve body 1 is a streamlined smooth curve structure with no corners. All corners are rounded.

[0067] Example 3 See Figure 6 As shown, the dual-seat regulating valve of the present invention includes a valve body 1, which has a front flow channel 11, a valve cavity 13 and a rear flow channel 12.

[0068] The valve body 1 is a three-way structure with an opening at the connection between the valve front flow channel 11, the valve rear flow channel 12 and the valve cover 7. The bottom of the valve body 1 is an integral structure without openings.

[0069] At the top of the valve cavity 13, an upper valve seat is formed by the mating structure of the upper sleeve 3 and the lower sleeve 2. At the bottom of the valve cavity 13, a lower valve seat is formed by the lower sleeve 2.

[0070] Specifically, within the valve cavity 13 of the valve body 1, a lower sleeve 2 is provided, which accommodates the lifting and lowering stroke range of the lower valve core 4, via the clamping structure of the valve cover 7. Above the valve cavity 13 of the valve body 1, an upper sleeve 3 is provided, which accommodates the lifting and lowering stroke range of the upper valve core 5.

[0071] The lower sleeve 2 and the upper sleeve 3 are integrally formed. The inner diameter of the lower sleeve 2 is smaller than that of the upper sleeve 3. That is, the lower sleeve 2 is formed with a coaxial stepped structure at the bottom of the upper sleeve 3, so that the inner top end of the lower sleeve 2 and the inner bottom end of the upper sleeve 3 are fitted with a stepped structure, and the outer top end of the lower sleeve 2 and the outer bottom end of the upper sleeve 3 are also fitted with a stepped structure. The outer edge of the bottom end of the upper sleeve 3 rests on the top of the valve cavity 13 through a sealing gasket.

[0072] At the bottom inner wall of the lower sleeve 2, a radially protruding structure forms a lower valve seat that mates with the lower valve core 4. The throttling diameter dg1 of the lower valve seat is approximately 0.72 times the nominal diameter DN.

[0073] At the top of the lower sleeve 2, a radially protruding structure forms an upper valve seat that mates with the upper valve core 5 at the bottom of the upper sleeve 3. The throttling diameter dg2 of the upper valve seat is approximately 3mm larger than the throttling diameter dg1 of the lower valve seat, i.e., dg2 = dg1 + 3mm.

[0074] Four lower throttling windows 21 are evenly distributed around the lower circumference of the lower sleeve 2.

[0075] Five fluid passages 22 are evenly distributed around the upper circumference of the lower sleeve 2, located below the upper valve seat. The total flow area of ​​the fluid passages 22 is greater than the total flow area of ​​the lower throttling window 21.

[0076] Four upper throttling windows 31 are evenly distributed around the lower circumference of the upper sleeve 3.

[0077] The lower sleeve 2 and the upper sleeve 3 are formed by turning seamless steel pipes or by integral forging.

[0078] The upper valve core 5 and lower valve core 4, coaxially connected to the valve stem 6, mate with the corresponding upper sleeve 3 and lower sleeve 2 on the upper and lower sides of the valve cavity 13. The upper end of the valve stem 6 is guided through the valve cover 7 connected to the upper part of the valve body 1, serving as a connection to the actuator. Simultaneously, the assembly structure of the upper and lower valve cores within the corresponding sleeves also forms a guiding fit structure, compensating for the lack of a guiding structure at the lower end of the valve stem 6. In other words, the lower valve core 4 and upper valve core 5 are guided during their lifting stroke through the through-mounting structure at the valve cover 7 and the assembly structure within the corresponding sleeves.

[0079] The lower valve core 4 has a flat structure in the height direction. The bottom outer periphery of the lower valve core 4 is formed with a beveled structure to form a lower core side sealing surface that matches the lower valve seat. The bottom edge of the lower core side sealing surface forms a lower core side bottom surface that is basically planar.

[0080] The upper valve core 5 has a flat structure in the height direction. The bottom outer periphery of the upper valve core 5 is formed with an upper core side sealing surface that matches the upper valve seat in a beveled structure. The bottom edge of the upper core side sealing surface forms an upper core side bottom surface that is basically planar.

[0081] The fluid medium entering through the inlet channel 11 flows upward and downward through the lower throttling window 21 of the lower sleeve 2 and the fluid channel 22 of the lower sleeve 2 in the valve cavity 13. After the flow is split, it passes over the outer wall of the valve cavity 13 and finally converges at the outlet channel 12.

[0082] At the outer tail of the valve cavity 13, there is a flat guide nozzle 14 extending horizontally into the valve downstream flow channel 12. The guide nozzle 14 is basically located at the center of the valve downstream flow channel 12, thereby branching the valve downstream flow channel 12 into a valve downstream branch channel 121 connecting the upper sleeve 3 and a valve downstream branch channel 122 connecting the lower sleeve 2.

[0083] The outer upper wall 131 of the valve cavity 13 (the area adjacent to the guide nozzle 14) and the guide top side 141 of the guide nozzle 14 form a smooth, streamlined transition at an angle of approximately 160°, which facilitates the smooth flow of the fluid medium at the guide nozzle 14 and reduces the impact with the fluid medium below. The outer lower wall 132 of the valve cavity 13 (the area adjacent to the guide nozzle 14) and the guide bottom side 142 of the guide nozzle 14 also form a smooth, streamlined transition at an angle of approximately 160°. Thus, the guide top side profile structure and the guide bottom side profile structure of the guide nozzle 14 are basically symmetrically formed.

[0084] The outline of the downstream branch channel 2 122 on the valve body 1 is formed by a smooth curve without sharp angles from front (upstream) to back (downstream). That is, the outline of the downstream branch channel 2 122 on the valve body 1 is a streamlined smooth curve structure with no corners. All corners are rounded.

[0085] Example 4 The dual-seat regulating valve of the present invention includes a valve body, which has a front flow channel, a valve cavity and a rear flow channel.

[0086] The valve body is a three-way structure with openings at the connection between the valve front flow channel, the valve rear flow channel, and the valve cover, while the bottom of the valve body is an integral structure without openings.

[0087] At the top of the valve cavity, an upper valve seat is formed by the mating structure of an upper sleeve and a lower sleeve. At the bottom of the valve cavity, a lower valve seat is formed by a lower sleeve.

[0088] Specifically, within the valve cavity of the valve body, a lower sleeve is provided to accommodate the lower valve core's lifting and lowering stroke range, within the superimposed structure between the upper and lower sleeves and the valve cover's clamping structure. An upper sleeve to accommodate the upper valve core's lifting and lowering stroke range is provided above the valve cavity of the valve body.

[0089] The lower sleeve and upper sleeve are separate structures, with the inner diameter of the lower sleeve being smaller than that of the upper sleeve. The top end of the lower sleeve and the bottom end of the upper sleeve are joined together at the top of the valve cavity using an interlocking stop. The outer edge of the bottom end of the upper sleeve rests on the top of the valve cavity via a sealing gasket.

[0090] At the bottom inner wall of the lower sleeve, a radially protruding structure forms a lower valve seat that mates with the lower valve core. The throttling diameter dg1 of the lower valve seat is approximately 0.55 times the nominal diameter DN.

[0091] At the top of the lower sleeve, a radially protruding structure forms an upper valve seat that mates with the upper valve core at the bottom of the upper sleeve. The throttling diameter dg2 of the upper valve seat is approximately 2 mm larger than the throttling diameter dg1 of the lower valve seat, i.e., dg2 = dg1 + 2 mm.

[0092] Eight lower throttling windows are evenly distributed around the lower circumference of the lower sleeve.

[0093] The upper circumference of the lower sleeve has six fluid passages that are evenly distributed below the upper valve seat. The total flow area of ​​the fluid passages is greater than the total flow area of ​​the lower throttling window.

[0094] Eight upper throttling windows are evenly distributed around the lower circumference of the upper sleeve.

[0095] The lower sleeve and the upper sleeve mentioned above are respectively machined from seamless steel pipes.

[0096] The upper and lower valve cores are coaxially connected to the valve stem, and mate with corresponding upper and lower sleeves on the upper and lower sides of the valve cavity. The upper end of the valve stem is guided through the valve cover connected to the upper part of the valve body and serves to connect to the actuator. At the same time, the assembly structure of the upper and lower valve cores in the corresponding sleeves also forms a guiding fit structure, compensating for the lack of a guiding structure at the lower end of the valve stem. In other words, the lower and upper valve cores are guided in their lifting stroke through the through-mounting structure at the valve cover and the assembly structure in the corresponding sleeves.

[0097] The lower valve core has a spherical crown-shaped structure with a basically flat top surface and a spherical crown protruding at the bottom in the height direction. The bottom spherical crown surface of the lower valve core forms the lower core side sealing surface that matches the lower valve seat.

[0098] The upper valve core has a spherical crown-shaped structure with a basically flat top surface and a spherical crown protruding at the bottom in the height direction. The bottom spherical crown surface of the upper valve core forms the upper core side sealing surface that matches the upper valve seat.

[0099] The fluid medium entering through the inlet channel of the valve flows upward and downward through the lower throttling window of the lower sleeve and the fluid channel of the lower sleeve in the valve cavity. After the flow is split, it passes over the outer wall of the valve cavity and finally converges at the outlet channel of the valve.

[0100] At the outer tail of the valve cavity, there is a flat guide nozzle that extends horizontally into the downstream flow channel. The guide nozzle is basically located at the center of the downstream flow channel, thus branching the downstream flow channel into downstream branch channel one that connects to the upper sleeve and downstream branch channel two that connects to the lower sleeve.

[0101] The outer upper wall of the valve cavity (the area near the guide nozzle) and the top side of the guide nozzle form a smooth, streamlined transition at an angle of approximately 135°. This facilitates smooth flow of the fluid medium at the guide nozzle and minimizes impact with the fluid medium below. Similarly, the outer lower wall of the valve cavity (the area near the guide nozzle) and the bottom side of the guide nozzle also form a smooth, streamlined transition at an angle of approximately 135°. Thus, the top and bottom profiles of the guide nozzle are essentially symmetrical.

[0102] The outline of the second downstream branch channel on the valve body is formed by a smooth curve without sharp angles from front (upstream) to back (downstream). That is, the outline of the second downstream branch channel on the valve body is a streamlined smooth curve structure with no corners. All corners are rounded.

[0103] Example 5 The dual-seat regulating valve of the present invention includes a valve body, which has a front flow channel, a valve cavity and a rear flow channel.

[0104] The valve body is a three-way structure with openings at the connection between the valve front flow channel, the valve rear flow channel, and the valve cover, while the bottom of the valve body is an integral structure without openings.

[0105] At the top of the valve cavity, an upper valve seat is formed by the mating structure of an upper sleeve and a lower sleeve. At the bottom of the valve cavity, a lower valve seat is formed by a lower sleeve.

[0106] Specifically, within the valve cavity of the valve body, a lower sleeve is installed using the valve cover's clamping structure to accommodate the lower valve core's lifting and lowering stroke range. Above the valve cavity of the valve body, an upper sleeve is installed to accommodate the upper valve core's lifting and lowering stroke range.

[0107] The lower sleeve and upper sleeve are integrally formed. The inner diameter of the lower sleeve is smaller than that of the upper sleeve. Specifically, the lower sleeve is formed with a coaxial stepped structure at the bottom of the upper sleeve, resulting in a stepped fit between the inner top and inner bottom of the lower sleeve, and also between the outer top and outer bottom of the lower sleeve. The outer edge of the bottom of the upper sleeve rests on the top of the valve cavity via a sealing gasket.

[0108] At the bottom inner wall of the lower sleeve, a radially protruding structure forms a lower valve seat that mates with the lower valve core. The throttling diameter dg1 of the lower valve seat is approximately 0.68 times the nominal diameter DN.

[0109] At the top of the lower sleeve, a radially protruding structure forms an upper valve seat that mates with the upper valve core at the bottom of the upper sleeve. The throttling diameter dg2 of the upper valve seat is approximately 4 mm larger than the throttling diameter dg1 of the lower valve seat, i.e., dg2 = dg1 + 4 mm.

[0110] The lower circumference of the lower sleeve has seven lower throttling windows that are basically evenly distributed.

[0111] Four fluid passages are evenly distributed around the upper circumference of the lower sleeve, located below the upper valve seat. The total flow area of ​​the fluid passages is greater than the total flow area of ​​the lower throttling window.

[0112] The lower circumference of the upper sleeve has seven upper throttling windows that are basically evenly distributed.

[0113] The aforementioned lower sleeve and upper sleeve are formed by turning seamless steel pipes or by integral forging.

[0114] The upper and lower valve cores are coaxially connected to the valve stem, and mate with corresponding upper and lower sleeves on the upper and lower sides of the valve cavity. The upper end of the valve stem is guided through the valve cover connected to the upper part of the valve body and serves to connect to the actuator. At the same time, the assembly structure of the upper and lower valve cores in the corresponding sleeves also forms a guiding fit structure, compensating for the lack of a guiding structure at the lower end of the valve stem. In other words, the lower and upper valve cores are guided in their lifting stroke through the through-mounting structure at the valve cover and the assembly structure in the corresponding sleeves.

[0115] The lower valve core has a spherical crown-shaped structure with a basically flat top surface and a spherical crown protruding at the bottom in the height direction. The bottom spherical crown surface of the lower valve core forms the lower core side sealing surface that matches the lower valve seat.

[0116] The upper valve core has a spherical crown-shaped structure with a basically flat top surface and a spherical crown protruding at the bottom in the height direction. The bottom spherical crown surface of the upper valve core forms the upper core side sealing surface that matches the upper valve seat.

[0117] The fluid medium entering through the inlet channel of the valve flows upward and downward through the lower throttling window of the lower sleeve and the fluid channel of the lower sleeve in the valve cavity. After the flow is split, it passes over the outer wall of the valve cavity and finally converges at the outlet channel of the valve.

[0118] At the outer tail of the valve cavity, there is a flat guide nozzle that extends horizontally into the downstream flow channel. The guide nozzle is basically located at the center of the downstream flow channel, thus branching the downstream flow channel into downstream branch channel one that connects to the upper sleeve and downstream branch channel two that connects to the lower sleeve.

[0119] The outer upper wall of the valve cavity (the area near the guide nozzle) and the top side of the guide nozzle form a smooth, streamlined transition at an angle of approximately 145°. This facilitates smooth flow of the fluid medium at the guide nozzle and minimizes impact with the fluid medium below. Similarly, the outer lower wall of the valve cavity (the area near the guide nozzle) and the bottom side of the guide nozzle also form a smooth, streamlined transition at an angle of approximately 145°. Thus, the top and bottom profiles of the guide nozzle are essentially symmetrical.

[0120] The outline of the second downstream branch channel on the valve body is formed by a smooth curve without sharp angles from front (upstream) to back (downstream). That is, the outline of the second downstream branch channel on the valve body is a streamlined smooth curve structure with no corners. All corners are rounded.

[0121] The above embodiments are only used to illustrate the present invention and are not intended to limit it; Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the present invention can still modify the specific technical solutions in the above embodiments or make equivalent substitutions for some of the technical features, and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the present invention.

Claims

1. A double-seat regulating valve, comprising a valve body (1); The valve body (1) has a front flow channel (11), a valve cavity (13) and a rear flow channel (12). The lower side of the valve cavity (13) is provided with a lower valve seat that cooperates with the lower valve core (4), and the upper side is provided with an upper valve seat that cooperates with the upper valve core (5). Its features are: The lower valve seat throttling diameter (dg1) at the lower valve seat is 0.50 to 0.90 times the nominal diameter (DN).

2. The dual-seat regulating valve according to claim 1, characterized in that: The throttling diameter (dg1) of the lower valve seat at the lower valve seat is 0.60 to 0.80 times the nominal diameter (DN); The upper valve seat throttling diameter (dg2) at the upper valve seat is 0.5 to 10 mm larger than the lower valve seat throttling diameter (dg1).

3. The dual-seat regulating valve according to claim 1, characterized in that: The valve body (1) is provided with a lower sleeve (2) that fits the lower valve core (4) within the valve cavity (13). A lower throttling window (21) is provided at the lower circumference of the lower sleeve (2). A fluid passage (22) is provided on the upper circumference of the lower sleeve (2) below the upper valve seat. The valve body (1) has an upper sleeve (3) above the valve cavity (13) that accommodates the lifting stroke range of the upper valve core (5). An upper throttling window (31) is provided at the lower circumference of the upper sleeve (3).

4. The dual-seat regulating valve according to claim 3, characterized in that: The lower sleeve (2) and the upper sleeve (3) are separate structures, and the inner diameter of the lower sleeve (2) is smaller than the inner diameter of the upper sleeve (3); The top end of the lower sleeve (2) and the bottom end of the upper sleeve (3) are joined together at the top of the valve cavity (13); The bottom inner wall of the lower sleeve (2) is provided with a radially protruding structure to form a lower valve seat that matches the lower valve core (4); The upper valve seat that mates with the upper valve core (5) is formed by a radially protruding structure at the top of the lower sleeve (2) and at the bottom of the upper sleeve (3).

5. The dual-seat regulating valve according to claim 3, characterized in that: The lower sleeve (2) and the upper sleeve (3) are integrally formed. The inner diameter of the lower sleeve (2) is smaller than the inner diameter of the upper sleeve (3). The lower sleeve (2) is fitted with the upper sleeve (3) at the bottom with a coaxial stepped structure. The bottom inner wall of the lower sleeve (2) is provided with a radially protruding structure to form a lower valve seat that matches the lower valve core (4); At the top of the lower sleeve (2) and at the bottom of the upper sleeve (3), a radially protruding structure is formed to form an upper valve seat that cooperates with the upper valve core (5).

6. The dual-seat regulating valve according to claim 3, characterized in that: The valve body (1) is a three-way structure with an opening at the connection between the valve front flow channel (11), the valve rear flow channel (12), and the valve cover (7); The lower valve core (4) and the upper valve core (5) are guided by the lifting stroke through the through-mount structure at the valve cover (7) and the assembly structure in the corresponding sleeve.

7. The dual-seat regulating valve according to claim 6, characterized in that: The valve downstream passage (12) has a valve downstream branch passage (122) that serves as a connection to the lower side of the valve chamber (13). The profile of the second branch channel (122) after the valve on the valve body (1) is formed by a smooth curve without sharp angles from front to back.

8. The dual-seat regulating valve according to claim 3, characterized in that: The lower valve core (4) has a flat structure in the height direction, and the bottom outer periphery of the lower valve core (4) is formed with a beveled structure to form a lower core side sealing surface (41) that matches the lower valve seat.

9. The dual-seat regulating valve according to claim 3, characterized in that: The upper valve core (5) has a flat structure in the height direction, and the bottom outer periphery of the upper valve core (5) is formed with an upper core side sealing surface (51) that matches the upper valve seat.

10. The dual-seat regulating valve according to claim 1 or 3, characterized in that: The outer tail of the valve cavity (13) has a flat guide nozzle (14) that extends horizontally into the flow channel (12) after the valve. The outer upper wall (131) of the valve cavity (13) and the top side (141) of the guide nozzle (14) are smoothly transitioned in a streamlined manner with an included angle of 120 to 160°. The lower outer wall (132) of the valve cavity (13) and the bottom side (142) of the guide nozzle (14) are smoothly transitioned in a streamlined shape with an included angle of 120 to 160°.

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