Differential pressure self-balancing single seat control valve

Abstract

The application discloses a differential pressure self-balancing single-seat regulating valve, which comprises a valve seat and a valve core arranged in a valve cavity of a valve body; the valve core is provided with a lower core-side sealing surface on a throttling curved surface, a balance hole is arranged between a top surface and the throttling curved surface, and an upper core-side sealing surface is arranged at an upper portion of the valve core; the valve cavity is located at an upper area of a post-valve flow channel, and is provided with a cavity-side sealing surface; when the valve core is lowered to a lowest position in the valve cavity, the lower core-side sealing surface is seated on a seat-side sealing surface to realize hard contact sealing cooperation, the pre-valve flow channel in the valve body is cut off from the post-valve flow channel, the upper core-side sealing surface is seated on the cavity-side sealing surface to realize hard contact sealing cooperation, and the valve cavity where the valve core is located is cut off from the post-valve flow channel. When the valve is closed, the two sealing structures at the upper and lower positions can realize stable and reliable synchronous sealing, and are not prone to failure and leakage faults, so that the valve can be reliably and stably served for a long time, and the application working condition environment is wide.

Description

TECHNICAL FIELD

[0001] The present application relates to a single seat regulating valve, in particular to a differential pressure self-balancing single seat regulating valve capable of working in full differential pressure (i.e. 0~nominal pressure PN) working condition environment. BACKGROUND

[0002] The regulating valve is the most commonly used and important terminal control element in the process control industry, i.e. the actuator, which receives the signal output by the control system to adjust the on / off state and opening degree of the valve, so as to achieve automatic adjustment of the control parameters such as pressure, temperature, flow, liquid level, etc.

[0003] Common regulating valves are divided into single seat regulating valves, double seat regulating valves, sleeve regulating valves, etc. according to the sealing structure. Among them, the single seat regulating valve has the technical characteristics of compact structure, small size, easy to form, small leakage, good regulating performance, etc.

[0004] The traditional single seat regulating valve is shown in Figure 1 which is mainly composed of a valve seat 2 and a valve core 3' arranged in the valve cavity of the valve body 1. The valve seat 2 is fixed on the throttling port in the valve cavity of the valve body 1 by a threaded structure, and is located between the valve front flow passage 11 and the valve rear flow passage 12. The bottom of the valve core 3' is a throttling curved surface structure; the valve core 3' is arranged in the valve cavity above the valve seat 2 through the valve stem 4, and under the drive of the valve stem 4, the valve core 3' can perform ascending / descending action in the valve cavity above the valve seat 2. When the valve core 3' descends to the lowest position in the valve cavity of the valve body 1, the sealing surface on the valve core 3' is seated on the sealing surface on the valve seat 2, cutting off the valve front flow passage 11 and the valve rear flow passage 12 in the valve body 1, realizing no leakage or little leakage; when the valve core 3' rises above the valve seat 2, the valve core 3' realizes the adjustment of the flow curve through the cooperation between the bottom throttling curved surface and the valve seat 2.

[0005] From the forming structure of the single seat regulating valve, its beneficial technical effects are:

[0006] -There is only one valve seat structure in the valve body, and the sealing surface between the sealing surface of the valve core and the sealing surface of the valve seat can achieve good contact sealing effect, so that the shut-off function of the valve can be easily realized, and the leakage is small;

[0007] -There is only one sealing structure between the valve core and the valve seat in the valve cavity, and the valve core and other structures in the valve cavity do not need to be sealed, which is beneficial to high-precision, high-efficiency and low-cost manufacturing, and also beneficial to compact structure and small size;

[0008] -The throttling curved surface structure at the bottom of the valve core is more easy to realize precise flow characteristics, and the regulating performance is good and stable.

[0009] From the forming structure of the single seat regulating valve, its technical problems are:

[0010] - the difference between the pressure at the front end of the throttling orifice (usually referred to as the pre-valve pressure, denoted as P1) and the pressure at the rear end of the throttling orifice (usually referred to as the post-valve pressure, denoted as P2) when the valve core is throttling - the working pressure difference (i.e., the pressure energy loss of throttling, denoted as ΔP) is ΔP = P1 - P2;

[0011] - when the valve is closed, the working pressure difference acts on the throttling surface and the sealing structure of the valve core, and the pressure at the front end of the throttling orifice is much greater than the pressure at the rear end of the throttling orifice, which is usually referred to as an unbalanced structure, and the pre-valve pressure easily pushes the valve core open; in order to ensure the sealing effect, the conventional technical measure is to limit the working pressure difference of the single-seat regulating valve (usually referred to as the allowable working pressure difference, denoted as [ΔP]), and the allowable working pressure difference decreases sharply with the increase of the throttling diameter.

[0012] In summary, the single-seat regulating valve has the technical characteristics of small leakage, good regulating performance (beneficial aspect) and small allowable working pressure difference (deficient aspect).

[0013] To solve the technical problem of small allowable working pressure difference of the single-seat regulating valve, the most effective technical measure is:

[0014] - a sleeve capable of surrounding the valve core is arranged in the valve cavity above the valve seat;

[0015] - a circumferentially shaped sealing groove is formed on the outer periphery of the upper part of the valve core or the inner periphery of the upper part of the sleeve, and a soft sealing ring is filled in the sealing groove;

[0016] - when the valve core is seated on the valve seat, the outer periphery of the upper part of the valve core and the inner periphery of the upper part of the sleeve are sealed by the sealing ring;

[0017] - a balance hole is arranged on the valve core to guide the fluid medium in the pre-valve flow passage to the top valve cavity of the valve core, so as to achieve the balance of the pre-valve and post-valve pressure difference;

[0018] For example, the technical documents disclosed in Chinese patent documents with the names of "a single-seat regulating valve" (publication number CN 211649074 U, publication date October 09, 2020), "a balanced single-seat regulating valve" (publication number CN 214743419 U, publication date November 16, 2021), "a single-seat pressure balance valve core type regulating valve" (publication number CN 201496568 U, publication date June 02, 2010) and the like.

[0019] The single-seat regulating valve capable of realizing differential pressure balance is sealed between the valve core and the sleeve by a soft sealing ring, that is, the second sealing structure in the valve cavity is realized by a soft sealing ring embedded in a sealing groove. The soft sealing ring is easy to wear (easily scratched in a fluid medium with impurities) during the reciprocating lifting / descending of the valve core, thereby causing failure and invalidation. Moreover, based on the temperature resistance limitation of the soft sealing ring, the soft sealing ring is not suitable for application in a working condition environment with a fluid medium temperature exceeding 250 DEG C (hereinafter referred to as a high-temperature working condition environment). In the high-temperature working condition environment, the soft sealing ring is softened by high temperature and is easy to produce rheological failure during the lifting / descending of the valve core and under the influence of the working condition pressure.

[0020] Therefore, the existing differential pressure balance type single-seat regulating valve has the technical problems of poor service reliability and relatively limited application working condition environment range. SUMMARY

[0021] The technical purpose of the present application is to provide a full-differential pressure single-seat regulating valve which can realize differential pressure self-balancing, can be reliably and stably served for a long time, and can be applied to various working condition environments with different temperatures and fluid media containing impurities, in view of the particularity of the single-seat regulating valve and the deficiencies of the prior art.

[0022] The technical solution adopted by the present application to achieve the technical purpose is as follows: a differential pressure self-balancing single-seat regulating valve, comprising a valve seat and a valve core arranged in a valve cavity of a valve body;

[0023] The valve seat is fixed on a throttling port in the valve cavity, and the valve seat has a seat side sealing surface matched with the valve core;

[0024] The valve core can perform lifting / descending action in the valve cavity above the valve seat through a valve stem. The bottom of the valve core has a throttling curved surface matched with the valve seat, and the throttling curved surface has a core side lower sealing surface matched with the seat side sealing surface. When the valve core is lowered to the lowest position in the valve cavity, the core side lower sealing surface is seated on the seat side sealing surface to realize a hard contact sealing fit, thereby cutting off the valve front flow passage and the valve rear flow passage in the valve body;

[0025] A balance hole capable of guiding the fluid medium in the valve front flow passage into the valve cavity is arranged between the top surface and the throttling curved surface of the valve core;

[0026] The upper part of the valve core has a circumferential outward convex shoulder structure, and the bottom edge of the shoulder structure has a core side upper sealing surface;

[0027] The valve cavity has a circumferential inward concave step structure in the area above the valve rear flow passage, and the step transition of the step structure has a cavity side sealing surface matched with the core side upper sealing surface;

[0028] When the spool is lowered to the lowest position in the valve cavity, the upper spool-side sealing surface is seated on the cavity-side sealing surface to achieve a hard-contact sealing fit, thereby cutting off the valve cavity where the spool is located from the post-valve flow passage.

[0029] The above technical measures are targeted at the particularity of single-seat regulating valves. On the basis of the balance hole between the top surface of the spool and the throttling curved surface, a convex shoulder structure is formed on the outer periphery of the upper part of the spool to form an upper spool-side sealing surface, and a step structure is formed on the inner periphery of the valve cavity in the area above the post-valve flow passage to form a cavity-side sealing surface. When the spool is seated on the valve seat, the upper spool-side sealing surface on the outer periphery of the upper part of the spool is simultaneously seated on the cavity-side sealing surface. In this way, two hard-contact sealing fit structures are formed in the valve cavity of the valve body, a first hard-contact sealing fit structure is between the throttling curved surface of the spool and the valve seat, and a second hard-contact sealing fit structure is between the upper part of the spool and the valve cavity in the area above the post-valve flow passage.

[0030] Compared with the structure of conventional single-seat regulating valves, when the valve is closed, the first and second hard-contact sealing fit structures are seated, thereby cutting off the pre-valve flow passage and the post-valve flow passage in the valve body. The fluid medium in the pre-valve flow passage is guided to the valve cavity at the rear end of the throttling port through the balance hole in the spool, and the pressure at the throttling curved surface of the spool tends to balance with the pressure at the top surface of the spool, thereby achieving differential pressure self-balancing regulation, i.e., a balanced structure with upper and lower seals is formed. This effectively solves the technical problem of small allowable working pressure difference of conventional single-seat regulating valves and enables the valve to work in full pressure difference (i.e., 0~PN) working conditions. At the same time, the valve still retains the technical features of conventional single-seat regulating valves, such as compact structure, small size, easy molding, small leakage, good regulation performance, etc.

[0031] Compared with the technologies disclosed in CN 211649074 U, CN 214743419 U, and CN 201496568 U, the two sealing structures at the upper and lower positions are both hard-contact sealing fit structures. When the valve is closed, the two sealing structures at the upper and lower positions can be stably and reliably seated synchronously and are not prone to sealing failure and leakage. Therefore, the valve can be reliably and stably served for a long time in the process control industry. At the same time, the two hard-contact sealing fit structures at the upper and lower positions are not affected by the temperature of the working condition environment and the impurities contained in the fluid medium. Therefore, the valve is suitable for various process control industries with different temperature working condition environments and fluid media containing impurities, and can be applied to a wide range of working condition environments.

[0032] As one of the preferred schemes, the convex shoulder structure has an outer convex height of ≤8 mm at the upper part of the spool.

[0033] The upper spool-side sealing surface at the bottom edge of the convex shoulder structure is a slope structure / curved surface structure for the slope transition between the outer edge of the convex shoulder structure and the spool body.

[0034] Further, the height of the shoulder structure at the upper part of the valve core is 1-4 mm.

[0035] The above technical measures, on the one hand, do not increase (at least not significantly) the structural volume of the valve core, on the other hand, the shoulder structure is beneficial to the molding of the upper core side sealing surface of the outer periphery of the upper part of the valve core, and on the third hand, the upper core side sealing surface formed by the inclined surface of the bottom of the shoulder structure can form a reliable setting effect on the cavity side sealing surface, and at the same time, limit the downward valve core on the corresponding setting structure.

[0036] As one of the preferred schemes, a pressure cage is further arranged in the valve cavity of the valve body, the bottom of the pressure cage abuts at the top of the valve seat, and the top abuts at the bottom of the valve cover connected to the valve body;

[0037] A plurality of flow channels capable of communicating the valve cavity where the valve core is located and the valve post flow passage are arranged around the pressure cage, and the total flow area of the flow channels is at least equal to the flow area of the valve seat under the full opening state of the valve core;

[0038] The cavity side sealing surface is formed on the inner wall of the pressure cage above the flow channels in a circumferentially recessed step structure.

[0039] The above technical measures, on the one hand, the pressure cage is pressed against the valve seat on the valve body, so that the fixing structure of the valve seat on the valve body is firm, and the molding and assembly structure is simple, which is convenient for later maintenance; on the other hand, the space surrounded by the pressure cage is used as the valve cavity for the reciprocating motion of the valve core, and the cavity side sealing surface, i.e. the cage side sealing surface, is formed on the inner periphery of the pressure cage, which is convenient for the manufacturing of the valve body and the pressure cage; on the third hand, the cooperation between the total flow area on the pressure cage and the flow area of the valve seat under the full opening state of the valve core makes the pressure cage only play the role of pressing the valve seat and cooperating with the second sealing between the valve core, without producing throttling regulation effect, so as to ensure that the flow of the fluid medium is not affected at the pressure cage, effectively avoid the increase of the structural volume of the valve cavity, and play the structural characteristics of the single seat regulating valve, thereby being different from the sleeve regulating valve which increases the valve cavity to install a large structural volume sleeve, so as to improve the structural characteristics of the fluid medium flow.

[0040] Further, the pressure cage is mainly composed of an annular bottom beam, an annular upper beam, and at least two vertical columns arranged between the bottom beam and the upper beam with a circumferential interval, and the flow channels are formed between the adjacent vertical columns between the bottom beam and the upper beam;

[0041] The bottom edge of the bottom beam is used as abutting the valve seat;

[0042] The top edge of the upper beam is used as abutting the valve cover.

[0043] The pressure cage can be stably matched with the valve cover and the valve seat, and has high structural strength, that is, the locking force of the valve cover on the valve body reliably acts on the valve seat, so that the valve seat is stably connected on the valve body.

[0044] Further, the vertical edges of the upright column of the pressure cage are rounded. The flow channel formed by the technical measure effectively reduces the flow resistance of the fluid medium flowing through the flow channel, and is beneficial to the smooth flow of the fluid medium at the pressure cage.

[0045] Further, the bottom of the pressure cage is a stepped structure with an outer edge downwardly outwardly protruding;

[0046] The top of the valve seat is a stepped structure with an outer edge downwardly inwardly recessed;

[0047] The bottom of the pressure cage and the top of the valve seat are in abutment and sealing cooperation in a concave-convex stop structure.

[0048] The technical measure does not affect the setting effect of the valve core on the valve seat, the matching structure between the pressure cage and the valve seat is stable, the mutual limiting effect is good, and the sealing effect of the matching part between the pressure cage and the valve seat is enhanced, and the leakage of the fluid medium at the matching part between the pressure cage and the valve seat is reduced (even eliminated).

[0049] Further, the top of the pressure cage is a stepped structure with an inner edge upwardly outwardly protruding;

[0050] The bottom of the valve cover serves as a region matched with the pressure cage, and is a stepped structure with an outer edge downwardly outwardly protruding;

[0051] The top of the pressure cage and the bottom of the valve cover are in abutment and sealing cooperation in a concave-convex stop structure.

[0052] The technical measure does not affect the upward displacement of the valve core in the valve cavity, especially in the valve cavity at the bottom of the valve cover; the matching structure between the pressure cage and the valve cover is stable, the mutual limiting effect is good, and the sealing effect of the matching part between the pressure cage and the valve cover is enhanced, and the leakage of the fluid medium at the matching part between the pressure cage and the valve cover is reduced (even eliminated).

[0053] As one of the preferred schemes, the valve core has a ring-shaped inwardly recessed flow expansion ring groove at the middle part thereof;

[0054] When the valve core descends to the lowest position in the valve cavity, the height position of the flow expansion ring groove is within the coverage range of the valve rear flow passage;

[0055] When the valve core ascends to the highest position in the valve cavity, the height position of the flow expansion ring groove is within the coverage range of the valve rear flow passage.

[0056] The technical measures above effectively increase the passage area of fluid medium from the throttling curved surface of the valve core to the valve rear flow channel between the valve core and the valve seat without increasing the passage area by increasing the diameter of the pressure cage, effectively avoiding the increase of the valve cavity structure volume, further reliably exerting the structural characteristics of the single-seat regulating valve, thereby distinguishing from the sleeve regulating valve which installs a large structural volume sleeve by increasing the valve cavity to improve the structural characteristics of fluid medium flow. At the same time, the valve core structure is substantially different from the valve plug of the sleeve regulating valve.

[0057] As one of the preferred solutions, the valve core is a hollow core structure mainly composed of an upper cylindrical segment and a lower curved housing segment, the inner space of the cylindrical segment is in an up-down through structure with the inner space of the curved housing segment;

[0058] The top of the cylindrical segment has an inwardly folded valve rod seat, the center of the valve rod seat is provided with a connection structure of the valve rod, and the outer periphery of the valve rod seat is composed of a plurality of through holes arranged at a circumferential interval and communicating with the inner space below to form a hollow structure;

[0059] The shoulder structure of the valve core and the upper core side sealing surface are formed at the upper part of the cylindrical segment;

[0060] The center of the curved housing segment is provided with a balance hole communicating with the inner space above, and the forming position of the balance hole on the curved housing segment is coaxially arranged with the forming position of the valve rod connection structure on the cylindrical segment;

[0061] The lower core side sealing surface of the valve core is formed at the upper part of the curved housing segment.

[0062] The valve core of the technical measures above has the following advantages: first, good balance is conducive to balanced stress, thereby effectively avoiding damage to the sealing surface between the valve core and the valve seat and the pressure cage caused by unbalanced stress; second, the curved housing segment has good stress, which is conducive to the hollow and thin-walled structure of the valve core, thereby reducing the material used for forming the valve core and reducing the cost; third, the outer periphery of the cylindrical segment and the inner periphery of the pressure cage can form a cylindrical surface cooperation, the valve core has good guidance and stability during ascending / descending reciprocation in the pressure cage, which is much better than the valve core with a traditional ball head structure (i.e. a simple curved housing segment).

[0063] Alternatively, as another alternative technical solution of the valve core above, the valve core is a solid core structure mainly composed of an upper cylindrical segment and a lower curved segment;

[0064] The top center of the cylindrical segment is provided with a connection structure of the valve rod, the shoulder structure of the valve core and the upper core side sealing surface are formed at the upper part of the cylindrical segment;

[0065] The lower core side sealing surface of the valve core is formed at the upper part of the curved segment;

[0066] The balance hole in the valve core is mainly composed of two hole segments arranged in upper and lower positions;

[0067] The first hole segment of the balance hole is vertically formed at the center of the curved segment, and the forming position of the first hole segment of the balance hole on the curved segment is coaxially arranged with the forming position of the valve rod connecting structure on the cylindrical segment;

[0068] The second hole segment of the balance hole is at least two inclined holes obliquely formed on the cylindrical segment, the upper end of each inclined hole is at the outer periphery of the valve rod connecting structure at the top of the cylindrical segment, the lower end is communicated with the first hole segment of the balance hole, and the inclined holes are rotationally symmetrically formed on the cylindrical segment with the axial direction of the valve rod connecting structure as the center.

[0069] The valve core with the above technical measures has good balance, is beneficial to balanced stress, thereby effectively avoiding damage to the sealing surface between the valve core and the valve seat and the pressure cage caused by unbalanced stress, and is much better than the dispersed arrangement structure of multiple balance holes on the circumference of the valve core; the stress is good; it is beneficial to the formation of the flow expansion ring groove; the outer periphery of the cylindrical segment and the inner periphery of the pressure cage can form a cylindrical surface cooperation, the guidance and stability of the valve core ascending / descending reciprocating in the pressure cage are good, and the valve core is much better than the valve core with a traditional ball head structure (i.e., a simple curved shell segment).

[0070] The beneficial technical effects of the present application are:

[0071] Compared with the traditional single-seat regulating valve structure, when the valve is closed, the first hard contact sealing cooperation structure and the second hard contact sealing cooperation structure are respectively seated and sealed, thereby cutting off the valve front flow passage and the valve rear flow passage in the valve body, the fluid medium in the valve front flow passage is guided to the valve cavity at the rear end of the throttling port through the balance hole on the valve core, the pressure at the throttling curved surface of the valve core tends to be balanced with the pressure at the top surface of the valve core, differential pressure self-balancing regulation is realized, i.e., a balanced structure with upper and lower double sealing is formed, the technical problem of small allowable working pressure difference of the traditional single-seat regulating valve is effectively solved, and the valve can work in a full pressure difference (i.e., 0~nominal pressure PN) working condition environment; at the same time, the structure of the traditional single-seat regulating valve is still retained, such as compact structure, small size, easy to form, small leakage, good regulation performance and the like.

[0072] Compared with the technologies disclosed in CN 211649074 U, CN 214743419 U and CN 201496568 U, the upper and lower two sealing structures are hard contact sealing structures, and when the valve is closed, the upper and lower two sealing structures can be stably and reliably synchronously seated, and are not prone to sealing failure and leakage failure, and can be reliably and stably served for a long time in the process control industry; meanwhile, the upper and lower two hard contact sealing structures are not affected by the temperature of the working condition environment and impurities contained in the fluid medium, and are suitable for the process control industry in various working condition environments of different temperatures and fluid medium impurities, and have a wide range of application working condition environments. BRIEF DESCRIPTION OF DRAWINGS

[0073] Figure 1 It is a structural schematic diagram of a traditional single-seat regulating valve.

[0074] Figure 2 It is a structural schematic diagram of the application.

[0075] Figure 3 It is a planar structural schematic diagram of the pressure cage in Figure 2 after unfolding.

[0076] Figure 4 It is a cooperation structural schematic diagram between the core side upper sealing surface and the cage side sealing surface in Figure 2 .

[0077] Figure 5 It is a cooperation structural schematic diagram between the core side lower sealing surface and the seat side sealing surface in Figure 2 .

[0078] Figure 6 It is another structural schematic diagram of the application.

[0079] Figure 7 It is a schematic diagram of fluid medium flowing from the valve cavity to the valve post-flow channel in the application of the single-seat regulating valve shown in Figure 6 .

[0080] Figure 8 It is a structural schematic diagram of a traditional sleeve regulating valve.

[0081] Figure 9 It is a planar structural schematic diagram of the sleeve in Figure 8 after unfolding.

[0082] Figure 10 It is a schematic diagram of fluid medium flowing from the valve cavity to the valve post-flow channel in the application of the sleeve regulating valve shown in Figure 8 .

[0083] Figure code meaning: 1 - valve body; 11 - valve front flow channel; 12 - valve rear flow channel; 2 - valve seat; 21 - seat side sealing surface; 3, 3' - valve core; 31 - balance hole; 32 - core side upper sealing surface; 33 - core side lower sealing surface; 34 - flow ring groove; 4 - valve stem; 5 - valve cover; 6 - pressure cage; 61 - bottom beam; 62 - upper beam; 63 - column; 64 - flow passage; 65 - cage side sealing surface; 7 - sleeve; 71 - throttling window; 8 - valve plug. DETAILED DESCRIPTION

[0084] The present application relates to a single seat regulating valve, in particular to a differential pressure self-balancing single seat regulating valve capable of working in full differential pressure (i.e. 0~nominal pressure PN) working condition environment. The technical content of the present application is described in detail in the following multiple embodiments, among which, the technical solution content of the present application is clearly and detailedly explained in combination with the drawings of the specification of Figure 2 、 Figure 3 、 Figure 4 and Figure 5 Embodiment 1; the technical solution content of the present application is clearly and detailedly explained in combination with the drawings of the specification of Figure 6 and Figure 7 Embodiment 2; the main structure of other embodiments, although not separately drawn, can still refer to the drawings of Embodiment 1 or Embodiment 2.

[0085] It needs to be particularly pointed out that the drawings of the present application are schematic, and unnecessary details have been simplified in order to avoid obscuring the technical solution of the present application which contributes to the prior art.

[0086] Embodiment 1

[0087] As shown in Figure 2 、 Figure 3 、 Figure 4 and Figure 5 , the present application includes a valve body 1, a valve seat 2, a valve core 3, a valve stem 4, a valve cover 5 and a pressure cage 6.

[0088] Among them, the valve body 1 is provided with a valve front flow channel 11, a valve cavity and a valve rear flow channel 12. The valve front flow channel 11 and the valve rear flow channel 12 are arranged in an upper and lower staggered manner at the valve cavity, which is approximately an S-shaped horizontal lying type. The top of the valve cavity is open for connecting the valve cover 5; the bottom of the valve cavity is used as a throttling port for connecting the valve seat 2.

[0089] The valve seat 2 is a ring structure.

[0090] The bottom of the valve seat 2 is a stepped structure with the outer edge upwardly concave. The bottom of the valve seat 2 is sleeved at the throttling port of the valve cavity inside the valve body 1 in a concave-convex stop structure, and the valve seat 2 and the valve body 1 form a hard contact sealing fit, and a sealing gasket structure can also be added at their sleeve joint.

[0091] The top of the valve seat 2 is a step structure with the outer edge downwardly concave, and the step structure of the outer edge of the top of the valve seat 2 is slightly higher than the throttle opening position in the valve body 1.

[0092] The inner edge of the top of the valve seat 2 is an outer convex camber structure (i.e. R convex surface), which constitutes the seat side sealing surface 21 of the valve seat 2 for cooperating with the valve core 3. The outer convex camber structure of the seat side sealing surface 21 not only has good sealing effect, but also is easy to be processed into a shape by a numerical control machine tool.

[0093] The pressing cage 6 is a ring-shaped cylindrical structure, which is mainly composed of a ring-shaped bottom beam 61, a ring-shaped upper beam 62, and at least two vertical columns 63 arranged between the bottom beam 61 and the upper beam 62 at an interval around the circumference. The adjacent vertical columns 63 between the bottom beam 61 and the upper beam 62 constitute a flow channel 64 that can communicate inside and outside.

[0094] The number of the above-mentioned vertical columns 63 is usually two to twelve, preferably three to eight. This can not only enhance the structural strength, but also be conducive to increasing the flow channel described below, and facilitate the molding. The vertical inner and outer corners of each vertical column 63 are respectively rounded corner structures, i.e. the planar outer contour of the vertical column 63 is in a circular shape, an elliptical shape or a waist-shaped hole shape, usually in a waist-shaped hole shape, which effectively balances the structural strength and reduces the resistance of the fluid medium.

[0095] The outer diameter of the pressing cage 6 substantially corresponds to the outer diameter of the valve seat 2. The inner diameter of the pressing cage 6 is slightly larger than the inner diameter of the valve seat 2, and necessarily smaller than the maximum outer diameter of the seat side sealing surface 21, so as to prevent the pressing cage 6 from causing positional interference with the seating of the valve core 3 on the valve seat 2.

[0096] The sum of the areas of each flow channel 64 around the circumference of the pressing cage 6, i.e. the total flow area of the flow channels 64 on the pressing cage 6, should at least be equal to (usually greater than, and preferably greater than, which can eliminate the throttling effect of the pressing cage on the fluid medium) the flow area at the valve seat 2 under the full open state of the valve core 3 (i.e. the flow area under the full open state of throttling).

[0097] The inner circumference at the upper part of the pressing cage 6, i.e. the inner circumference of the upper beam 62 of the pressing cage 6, is formed with a step structure in a circumferential concave structure, and the radial depth of the step structure is about 2 mm. The inner edge at the bottom of the step structure on the pressing cage 6 is an outer convex camber structure, which constitutes the cage side sealing surface 65 (i.e. the cavity side sealing surface) of the pressing cage 6 for cooperating with the seating of the valve core 3 described below. That is, the cage side sealing surface 65 on the pressing cage 6 is formed on the inner wall above the flow channel 64 of the pressing cage 6. Similarly, the outer convex camber structure of the cage side sealing surface 65 not only has good sealing effect, but also is easy to be processed into a shape by a numerical control machine tool.

[0098] The pressure cage 6 is arranged in the valve cavity of the valve body 1 to form the moving space of the valve core 3. Therefore, the bottom beam 61 of the pressure cage 6 is arranged to abut against the valve seat 2, and the upper beam 62 of the pressure cage 6 is arranged to abut against the valve cover 5.

[0099] The bottom of the bottom beam 61 of the pressure cage 6 is formed with a step structure with the outer edge outwardly protruding downward, which is basically matched with the step structure of the outer edge of the top of the valve seat 2. The bottom of the bottom beam 61 of the pressure cage 6 is arranged on the step structure of the outer edge of the top of the valve seat 2, that is, the bottom of the pressure cage 6 is arranged in abutting fit with the top of the valve seat 2 in the concave-convex stop structure, thereby forming a hard contact sealing fit structure, and the inner wall of the bottom of the pressure cage 6 is arranged outside the seat side sealing surface 21 on the valve seat 2. In the fit structure of the pressure cage 6 and the valve seat 2, the bottom edge of the flow channel 64 on the pressure cage 6 is slightly higher than the top surface of the valve seat 2.

[0100] The top of the upper beam 62 of the pressure cage 6 is formed with a step structure with the inner edge outwardly protruding upward, which is arranged to fit with the valve cover 5.

[0101] The valve cover 5 is sealingly connected to the top of the valve cavity of the valve body 1 by a plurality of circumferentially arranged bolts to block the valve cavity of the valve body 1, and has a concave chamber formed in the center of the bottom of the valve cover 5. When the valve cover 5 is combined with the valve body 1, the chamber in the bottom of the valve cover 5 and the valve cavity in the valve body 1 jointly form the valve cavity for the valve core 3 to reciprocate upward and downward.

[0102] The bottom of the valve cover 5 is arranged to fit with the top of the pressure cage 6, and is formed with a step structure with the outer edge outwardly protruding downward, which is basically matched with the step structure of the top of the upper beam 62 of the pressure cage 6. The valve cover 5 is blocked on the valve body 1, and the step structure of the bottom of the valve cover 5 is arranged in abutting fit with the top of the upper beam 62 of the pressure cage 6 in the concave-convex stop structure, thereby forming a hard contact sealing fit structure. Of course, a sealing gasket can be filled between them.

[0103] The valve core 3 is a hollow structure, which is mainly composed of a cylindrical segment at the top and a curved housing segment at the bottom, and the inner space of the cylindrical segment is in up-down through connection with the inner space of the curved housing segment. The valve core 3 is formed with a valve rod seat at the top of the cylindrical segment, which is inwardly folded. A connection structure of the valve rod 4, usually a threaded hole structure, is arranged in the center of the valve rod seat, and the outer periphery of the valve rod seat is formed with a hollow structure composed of a plurality of through holes arranged at substantially equal intervals in the circumferences and connected with the inner space below. The valve core 3 is formed with a balance hole 31 in the center of the curved housing segment, which is connected with the inner space above. The forming position of the balance hole 31 on the curved housing segment is substantially coaxially arranged with the forming position of the valve rod connection structure on the cylindrical segment, so that the valve core 3 can be substantially balanced when the balance hole 31 is drained. The outer surface of the curved housing segment of the valve core 3 is at the bottom of the valve core 3, which is arranged to fit with the throttle curve of the valve seat 2.

[0104] Valve core 3 is arranged in the valve cavity of the valve body 1 by the valve stem 4, above the valve seat 2, and in the axial range of the space surrounded by the pressure cage 6. The valve stem 4 extends upward through the valve cover 5 and is sealed by a sealing assembly. The valve core 3 can be lifted and lowered in the valve cavity above the valve seat 2 under the action of the valve stem 4.

[0105] The upper part of the throttling curved surface of the valve core 3 has a beveled structure (or a concave curved surface structure, i.e. R concave surface) - namely the core side lower sealing surface 33, which serves as a matching seat side sealing surface 21 on the valve seat 2. When the valve core 3 is lowered to the lowest position in the valve cavity, the core side lower sealing surface 33 is just seated on the seat side sealing surface 21, thereby achieving a hard contact sealing fit, cutting off the valve front flow passage 11 and the valve rear flow passage 12 in the valve body 1 (the cut-off state here can ignore the existence of the balance hole 31).

[0106] Due to the existence of the balance hole 31 on the valve core 3, a sealing structure is needed between the upper part of the valve core 3 and the pressure cage 6 when the valve is closed, to cut off the communication between the valve cavity and the valve rear flow passage 12. In order to achieve reliable sealing between the valve core 3 and the pressure cage 6, the upper part of the valve core 3 has a circumferential outward convex shoulder structure, i.e. the shoulder structure of the valve core 3 is formed at the upper part of the cylindrical section of the valve core 3. The outward convex height of the shoulder structure on the valve core 3 basically matches the step structure of the inner wall of the upper beam 62 of the pressure cage 6, i.e. the outward convex height is about 2mm; and the forming position of the shoulder structure on the valve core 3 is such that when the valve core 3 is seated on the valve seat 2, the bottom of the shoulder structure matches the bottom of the step structure of the inner wall of the upper beam 62.

[0107] The outer edge of the shoulder structure of the valve core 3 and the body of the valve core 3 are transitioned by a slope, forming a beveled structure (or a concave curved surface structure, i.e. R concave surface), which is the core side upper sealing surface 32, i.e. the core side upper sealing surface 32 of the valve core 3 is formed at the upper part of the cylindrical section. When the valve core 3 is lowered to the lowest position in the valve cavity, the core side upper sealing surface 32 is seated on the cage side sealing surface 65 in the pressure cage 6, achieving a hard contact sealing fit, cutting off the valve cavity where the valve core 3 is located and the valve rear flow passage 12.

[0108] Thus, when the valve core 3 is lowered to the lowest position in the valve cavity of the valve body 1, the lower sealing surface 33 of the core side is seated on the seat side sealing surface 21, and the upper sealing surface 32 of the core side is seated on the cage side sealing surface 65, cutting off the valve rear flow passage 12 from the valve front flow passage 11 and the valve cavity where the valve core 3 is located, but under the action of the balance hole 31 on the valve core 3, the valve cavity where the valve core 3 is located is in communication with the valve front flow passage 11, thereby guiding the fluid medium in the valve front flow passage 11 to the rear end of the throttling port, making the pressure at the front end of the throttling port and the pressure at the rear end of the throttling port tend to be balanced, realizing differential pressure self-balancing regulation, i.e., full differential pressure (0~PN) operation, completely solving the technical problem of small allowable working differential pressure of traditional single-seat regulating valves, and not being affected by the temperature and impurities contained in the fluid medium.

[0109] Embodiment 2

[0110] Referring to Figure 6 and Figure 7 The present application comprises a valve body 1, a valve seat 2, a valve core 3, a valve stem 4, a valve cover 5, and a pressure cage 6.

[0111] The valve body 1 is internally provided with a valve front flow passage 11, a valve cavity, and a valve rear flow passage 12. The valve front flow passage 11 and the valve rear flow passage 12 are arranged in an up-down staggered manner at the valve cavity to form an approximate horizontal S shape. The top of the valve cavity is open for connecting the valve cover 5, and the bottom of the valve cavity is a throttling port for connecting the valve seat 2.

[0112] The valve seat 2 is annular in structure. The bottom of the valve seat 2 is a stepped structure with the outer edge concave inward upward. The bottom of the valve seat 2 is fitted into the throttling port of the valve cavity in the valve body 1 in a concave-convex stop structure, forming a hard contact sealing fit between the valve seat 2 and the valve body 1, and a sealing gasket structure can also be added at their fitting position.

[0113] The top of the valve seat 2 is a stepped structure with the outer edge concave inward downward, and the stepped structure of the outer edge of the top of the valve seat 2 is slightly higher than the position of the throttling port in the valve body 1.

[0114] The inner edge of the top of the valve seat 2 is an outer convex curved surface structure, which constitutes the seat side sealing surface of the valve seat 2 for cooperating with the valve core 3. The outer convex curved surface structure of the seat side sealing surface not only has good sealing effect, but also is easy to be machined by a numerical control machine tool.

[0115] The pressure cage 6 is a cylindrical annular structure, which mainly comprises a ring-shaped bottom beam 61, a ring-shaped upper beam 62, and at least two vertical columns 63 arranged between the bottom beam 61 and the upper beam 62 at an annular interval, and a flow channel 64 capable of communicating inside and outside is formed between adjacent vertical columns 63 between the bottom beam 61 and the upper beam 62.

[0116] The number of the above-mentioned upright columns 63 is usually two to twelve, preferably three to eight, so as to enhance the structural strength, facilitate the increase of the flow passage and facilitate the molding.

[0117] The outer diameter of the pressing cage 6 is substantially equal to the outer diameter of the valve seat 2. The inner diameter of the pressing cage 6 is slightly larger than the inner diameter of the valve seat 2 and is necessarily smaller than the maximum outer diameter of the seat-side sealing surface 21, so as to prevent the pressing cage 6 from interfering with the seating of the valve core 3 on the valve seat 2.

[0118] The sum of the areas of the flow passages 64 around the circumference of the pressing cage 6, i.e. the total flow area of the flow passages 64 on the pressing cage 6, should be at least equal to (usually greater than, and preferably greater than, so as to eliminate the throttling effect of the pressing cage on the fluid medium) the flow area at the valve seat 2 under the full opening state of the valve core 3 (i.e. the flow area under the full opening state of throttling).

[0119] The inner circumference at the upper portion of the pressing cage 6, i.e. the inner circumference of the upper beam 62 of the pressing cage 6, is formed with a circumferential concave structure having a stepped structure with a radial depth of about 4 mm. The inner edge at the bottom of the stepped structure on the pressing cage 6 is formed with an outer convex curved surface structure, which constitutes the cage-side sealing surface (i.e. the cavity-side sealing surface) of the pressing cage 6 and the valve core 3 to be seated and matched. That is, the cage-side sealing surface on the pressing cage 6 is formed on the inner wall above the flow passage 64 of the pressing cage 6. Similarly, the outer convex curved surface structure of the cage-side sealing surface not only has good sealing effect, but also is easy to be machined by a numerical control machine tool.

[0120] The pressing cage 6 is arranged in the valve cavity of the above-mentioned valve body 1 to form a movement space for the valve core 3. Therefore, the bottom beam 61 of the pressing cage 6 is used to abut against the valve seat 2, and the upper beam 62 of the pressing cage 6 is used to abut against the valve cover 5.

[0121] The bottom of the bottom beam 61 of the pressing cage 6 is formed with a stepped structure with an outer edge outwardly convex downward, which substantially matches the stepped structure of the outer edge of the top of the above-mentioned valve seat 2. The bottom of the bottom beam 61 of the pressing cage 6 is seated on the stepped structure of the outer edge of the top of the above-mentioned valve seat 2, i.e. the bottom of the pressing cage 6 and the top of the valve seat 2 are abutted and matched with a concave-convex stop structure, thereby forming a hard contact sealing matching structure, and the inner wall of the bottom of the pressing cage 6 is outside the seat-side sealing surface on the valve seat 2. In the above-mentioned matching structure of the pressing cage 6 and the valve seat 2, the bottom edge of the flow passage 64 on the pressing cage 6 is slightly higher than the top surface of the valve seat 2.

[0122] The top of the upper beam 62 of the pressing cage 6 is formed with a stepped structure with an inner edge outwardly convex upward, which is used to cooperate with the valve cover 5.

[0123] The valve cover 5 is sealingly connected to the top of the valve cavity of the valve body 1 by a plurality of circumferentially arranged bolts, and blocks the valve cavity on the valve body 1. The bottom of the valve cover 5 has a concave shaped cavity. When the valve cover 5 is combined with the valve body 1, the cavity of the bottom of the valve cover 5 and the valve cavity in the valve body 1 together form a valve cavity for the poppet 3 to reciprocate up and down.

[0124] The bottom of the valve cover 5 serves as an area to fit the top of the pressure cage 6, and has a downwardly convex shaped step structure which substantially matches the step structure of the top of the upper beam 62 of the pressure cage 6. The valve cover 5 is blocked on the valve body 1, and is in abutting fit with the top of the upper beam 62 of the pressure cage 6 by the step structure of the bottom, in a concave-convex stop structure, to form a hard contact sealing fit structure. Of course, a gasket can be filled between them.

[0125] The poppet 3 is a solid core structure (the solid core here ignores the structure of the balance hole 31 described below), which is mainly composed of a cylindrical segment at the top and a curved segment at the bottom. The top center of the cylindrical segment is provided with a connection structure of the valve stem 4, usually a threaded hole structure.

[0126] The poppet 3 is provided with a balance hole 31, which is mainly composed of two hole segments arranged above and below. The first hole segment of the balance hole 31 is vertically formed at the center of the curved segment of the poppet 3, and the forming position of the first hole segment on the curved segment is substantially coaxially arranged with the forming position of the valve stem connection structure on the cylindrical segment. The second hole segment of the balance hole 31 is at least two (usually 2 to 4) inclined holes formed obliquely on the cylindrical segment. The upper end of each inclined hole is at the outer periphery of the valve stem connection structure at the top of the cylindrical segment, and the lower end is in communication with the first hole segment. These inclined holes are substantially rotationally symmetrically formed on the cylindrical segment with the axial direction of the valve stem connection structure as the center, so that the poppet 3 can be substantially balanced when the balance hole 31 is drained.

[0127] The outer surface of the curved segment of the poppet 3 is at the bottom of the poppet 3, which serves as the bottom of the poppet 3 to fit the throttling curve of the valve seat 2.

[0128] The poppet 3 is arranged in the valve cavity of the valve body 1 by the valve stem 4, above the valve seat 2, and within the axial range of the space surrounded by the pressure cage 6. The valve stem 4 extends upward through the valve cover 5 by a sealing assembly. Under the drive of the valve stem 4, the poppet 3 can reciprocate up and down in the valve cavity above the valve seat 2.

[0129] The upper part of the throttling curved surface of the valve core 3 has a slope structure (or an inner concave curved surface structure, i.e. R concave surface) - namely a core side lower sealing surface, which is used to match the seat side sealing surface 21 on the valve seat 2. When the valve core 3 is lowered to the lowest position in the valve cavity, the core side lower sealing surface is just seated on the seat side sealing surface, thereby achieving a hard contact sealing matching relationship, and cutting off the valve front flow channel 11 in the valve body 1 from the valve rear flow channel 12 (the cut-off state here can ignore the existence of the balance hole 31).

[0130] Due to the existence of the balance hole 31 on the valve core 3, a sealing structure is needed between the upper part of the valve core 3 and the pressure cage 6 when the valve is closed, so as to cut off the communication between the valve cavity and the valve rear flow channel 12. In order to achieve reliable sealing between the valve core 3 and the pressure cage 6, the upper part of the valve core 3 has a circumferential outward convex shoulder structure, i.e. the shoulder structure of the valve core 3 is formed at the upper part of the cylindrical section of the valve core 3. The outward convex height of the shoulder structure on the valve core 3 is basically matched with the step structure of the inner wall of the upper beam 62 of the pressure cage 6, i.e. the outward convex height is about 4 mm; and the forming position of the shoulder structure on the valve core 3 is that the bottom of the shoulder structure is matched with the bottom of the step structure of the inner wall of the upper beam 62 when the valve core 3 is seated on the valve seat 2.

[0131] The outer edge of the shoulder structure of the valve core 3 and the body of the valve core 3 are transitioned by a slope surface, forming a slope structure (or an inner concave curved surface structure, i.e. R concave surface), which is a core side upper sealing surface, i.e. the core side upper sealing surface of the valve core 3 is formed at the upper part of the cylindrical section. When the valve core 3 is lowered to the lowest position in the valve cavity, the core side upper sealing surface is seated on the cage side sealing surface in the pressure cage 6, achieving a hard contact sealing matching relationship, and cutting off the valve cavity where the valve core 3 is located from the valve rear flow channel 12.

[0132] In this way, when the valve core 3 is lowered to the lowest position in the valve cavity of the valve body 1, the core side lower sealing surface is seated on the seat side sealing surface, and the core side upper sealing surface is seated on the cage side sealing surface, cutting off the valve rear flow channel 12 from the valve front flow channel 11 and the valve cavity where the valve core 3 is located, but under the action of the balance hole 31 on the valve core 3, the valve cavity where the valve core 3 is located is communicated with the valve front flow channel 11, thereby guiding the fluid medium in the valve front flow channel 11 to the rear end of the throttling port, making the pressure at the front end of the throttling port and the pressure at the rear end of the throttling port tend to be balanced, achieving differential pressure self-balancing regulation, i.e. full differential pressure (0~PN) working, completely solving the technical problem that the allowable working differential pressure of the traditional single seat regulating valve is small, and not being affected by the temperature and impurities contained in the fluid medium.

[0133] In order to effectively increase the passage area of the fluid medium from the throttling surface of the valve core 3 to the valve rear flow passage 12 through the outer periphery of the valve core 3, an annular expansion ring groove 34 is formed in the middle of the valve core 3. The expansion ring groove 34 is located in the area between the lower core side sealing surface and the upper core side sealing surface. When the valve core 3 is lowered to the lowest position in the valve chamber or raised to the highest position, the height position of the expansion ring groove 34 is just within the coverage range of the upstream end of the valve rear flow passage 12. When the valve core 3 is raised to the highest position in the valve chamber, the height position of the expansion ring groove 34 can be blocked by the upper beam 62 of the pressure cage 6. The fluid medium flowing out of the throttling port directly flows into the valve rear flow passage 12 through the flow passage 64 on the pressure cage 6, without passing through the outer periphery of the valve core 3.

[0134] Referring to Figure 7 , the fluid medium flows directly to the valve rear flow passage through the expansion ring groove of the valve core after throttling. In order to make the flow rate of the fluid medium change as much as possible, the size of the pressure cage and the diameter of the valve chamber of the valve body should not be designed too large (too large will reduce the flow rate of the fluid medium, which is not conducive). It can be seen that it is beneficial to the compactness and miniaturization of the entire valve body structure, which is a significant difference from the sleeve regulating valve.

[0135] Referring to Figure 8 , Figure 9 and Figure 10 , the technical features of the traditional sleeve regulating valve and the traditional single seat regulating valve are:

[0136] - The sleeve 7 abuts against the throttling port in the valve body 1 through the valve cover 5, and a plurality of throttling windows 71 are arranged in the bottom annular space of the sleeve 7;

[0137] - The inner peripheral area of the bottom of the throttling window 71 forms the lower cylinder side sealing surface, and the inner peripheral area of the upper part of the throttling window 71 forms the upper cylinder side sealing surface;

[0138] - The valve plug 8 (equivalent to the valve core of the single seat regulating valve) is in a cylindrical or columnar structure, usually an open-bottomed cylindrical structure with a hollow core, and the outer periphery of the valve plug 8 is arranged with a plurality of balance holes communicating with the bottom and the top;

[0139] - The outer peripheral area of the bottom of the valve plug 8 and the inner peripheral area of the bottom of the throttling window 71 of the sleeve 7, and the outer peripheral area of the top of the valve plug 8 and the inner peripheral area of the upper part of the throttling window 71 of the sleeve 7, form an upper and lower double sealing structure, which is used to cut off the valve rear flow passage 12 and the valve chamber. However, there is no throttling between the valve plug 8 and the inner peripheral area of the bottom of the throttling window 71 of the sleeve 7, and the throttling is realized by the cooperation between the valve plug 8 and the throttling window 71 of the sleeve 7, which is a significant difference from the structure of the single seat regulating valve.

[0140] From the throttling area of the sleeve regulating valve, the throttling area of the sleeve regulating valve is realized by the throttling window 71 opened on the sleeve 7. The single seat regulating valve and the double seat regulating valve are realized by the cooperation between the throttling curved surface of the valve core bottom and the valve seat. It can be seen that the process of the single seat regulating valve is much simpler than that of the sleeve regulating valve.

[0141] From the flow path of the fluid medium, after the fluid medium flows through the throttling port (the throttling channel formed between the lower sealing surface of the valve plug 8 and the throttling window 71), it must flow to the valve rear flow channel 12 (see Figure 10 The valve cavity volume of the valve body is increased, and finally the structural volume and weight of the valve body are increased; on the other hand, since the throttling area of the sleeve regulating valve is opened on the circumference of the sleeve 7 (see Figure 9 The fluid medium can only flow to the valve rear flow channel 12 through the throttling window 71 on the sleeve 7, in order to ensure the flow area, the valve cavity volume must be sufficient, and in order to ensure the area of the throttling window 71, the diameter of the sleeve 7 must be increased, that is, only the valve cavity volume of the valve body can be increased to compensate for the insufficient flow area, and only the diameter of the sleeve 7 can be increased to compensate for the insufficient window area, and the technical problems brought by the increase of the sleeve 7 are:

[0142] The valve plug is correspondingly increased;

[0143] The valve cavity volume of the valve body is correspondingly increased;

[0144] Further, the wall thickness of the sleeve, the valve plug and the valve body is also correspondingly increased.

[0145] Without doubt, this will further increase the volume, weight and cost of the sleeve regulating valve, and the larger the caliber, the more obvious it is.

[0146] Compared with the above-mentioned sleeve regulating valve, the sleeve regulating valve of the present application adopts a pressure cage structure and a balanced structure with upper and lower double seals, but also reliably takes into account the structural characteristics of the single seat regulating valve, has the technical characteristics of simple flow path, small volume, light weight and low cost, and is substantially different from and significantly superior to the traditional sleeve regulating valve.

[0147] Embodiment 3

[0148] The other contents of this embodiment are the same as those of embodiment 1, except that:

[0149] The middle part of the valve core has a flow expansion ring groove recessed around the circumference.

[0150] Embodiment 4

[0151] The other contents of this embodiment are the same as those of Embodiment 1 or Embodiment 2, except that:

[0152] The inner edge of the top of the valve seat is a beveled structure, which constitutes the seat side sealing surface of the valve seat for cooperating with the valve core.

[0153] Embodiment 5

[0154] The other contents of this embodiment are the same as those of Embodiment 1, except that:

[0155] The inner edge of the bottom of the stepped structure of the inner periphery of the upper beam of the pressing cage is a beveled structure, which constitutes the cage side sealing surface (i.e., the cavity side sealing surface) of the pressing cage for cooperating with the valve core to be seated.

[0156] Embodiment 6

[0157] The present application comprises a valve body, a valve seat, a valve core, a valve stem, and a valve cover.

[0158] The valve body is internally provided with a valve front flow channel, a valve cavity, and a valve rear flow channel. The valve front flow channel and the valve rear flow channel are arranged in an up-down staggered manner at the valve cavity to form an approximate horizontal S shape. The top of the valve cavity is open for connecting the valve cover. The bottom of the valve cavity serves as a throttling port for connecting the valve seat. A threaded structure is provided at the throttling port of the valve body.

[0159] The valve seat is annular in structure. The bottom of the valve seat is a stepped structure with an outwardly concave top. A threaded structure is provided at the stepped structure of the bottom of the valve seat, which matches the threaded structure at the throttling port of the valve body. The valve seat is hard contact sealed and connected to the throttling port of the valve body by the threaded structure.

[0160] The top of the valve seat is slightly higher than the position of the throttling port in the valve body. The inner edge of the top of the valve seat is an outwardly convex curved surface structure, which constitutes the seat side sealing surface of the valve seat for cooperating with the valve core.

[0161] The valve cover is sealed and connected to the top of the valve cavity of the valve body by a plurality of circumferentially arranged bolts, thereby plugging the valve cavity on the valve body. The bottom of the valve cover has a concave cavity. When the valve cover and the valve body are combined together, the cavity at the bottom of the valve cover and the valve cavity in the valve body jointly constitute a valve cavity for the reciprocating lifting / descending of the valve core.

[0162] In order to enable the valve cavity at the bottom of the valve cover to form a sealing cooperation with the upper outer periphery of the valve core, a downwardly extending guide cylinder is connected at the connection between the valve cover and the valve body. The bottom end of the guide cylinder is substantially aligned with the upper edge of the upstream end of the valve rear flow channel on the valve body, or slightly lower than the upper edge of the upstream end of the valve rear flow channel. As can be seen, the guide cylinder is spaced apart from the valve seat below.

[0163] The inner periphery at the upper part of the guide cylinder is formed with a stepped structure in a circumferential concave structure, and the radial depth of the stepped structure is about 1.5 mm. The inner edge at the bottom of the stepped structure of the guide cylinder is formed with an outer convex curved surface structure, which constitutes a cavity side sealing surface of the guide cylinder and the seat sealing surface of the valve core.

[0164] The valve core is a hollow structure, which is mainly composed of a cylindrical segment at the upper part and a curved housing segment at the lower part. The inner space of the cylindrical segment is in communication with the inner space of the curved housing segment. The top of the cylindrical segment of the valve core is provided with a valve rod seat formed by inward folding. The center of the valve rod seat is provided with a connecting structure of the valve rod, which is usually a threaded hole structure. The outer periphery of the valve rod seat is formed with a hollow structure composed of a plurality of through holes arranged at substantially equal intervals in a circumferential direction and communicating with the inner space below. The center of the curved housing segment of the valve core is provided with a balance hole communicating with the inner space above. The balance hole is formed at a position on the curved housing segment, which is substantially coaxially arranged with the valve rod connecting structure on the cylindrical segment, so that the valve core can be substantially balanced when the balance hole is drained.

[0165] The valve core is arranged in the valve cavity of the valve body through the valve rod, above the valve seat, and the upper part of the valve core is always in the axial range above the space surrounded by the guide cylinder. The valve rod extends upward through the valve cover and is sealed by the sealing assembly. Under the driving of the valve rod, the valve core can perform ascending / descending action in the valve cavity above the valve seat.

[0166] The upper part of the throttling curved surface of the valve core is provided with a bevel structure (or an inwardly concave curved surface structure, i.e. R-concave surface), which is a core side lower sealing surface and is used to cooperate with the seat side sealing surface on the valve seat. When the valve core is lowered to the lowest position in the valve cavity, the core side lower sealing surface is just seated on the seat side sealing surface, thereby realizing a hard contact sealing cooperation, and cutting off the valve front flow passage and the valve rear flow passage in the valve body (the cutting-off state can ignore the existence of the balance hole).

[0167] Due to the existence of the balance hole on the valve core, a sealing structure is needed between the upper part of the valve core and the guide cylinder to cut off the communication between the valve cavity and the valve rear flow passage when the valve is closed. In order to realize reliable sealing between the valve core and the guide cylinder, the upper part of the valve core is provided with a circumferential outward convex shoulder structure, which is formed on the upper part of the cylindrical segment of the valve core. The outward convex height of the shoulder structure on the valve core is substantially matched with the stepped structure of the inner wall of the guide cylinder, i.e. the outward convex height is about 1.5 mm. The forming position of the shoulder structure on the valve core is matched with the bottom of the stepped structure of the inner wall of the guide cylinder when the valve core is seated on the valve seat.

[0168] The shoulder structure outer edge of the valve core is transitioned with the valve core body by a slope surface to form a bevel structure (or a concave curved surface structure, i.e. R concave surface), which is the upper core side sealing surface of the valve core. When the valve core is lowered to the lowest position in the valve cavity, the upper core side sealing surface is seated on the cavity side sealing surface in the guide cylinder to achieve a hard contact sealing fit, thereby cutting off the valve cavity where the valve core is located and the flow passage behind the valve.

[0169] Thus, when the valve core is lowered to the lowest position in the valve cavity of the valve body, the lower core side sealing surface is seated on the seat side sealing surface, and the upper core side sealing surface is seated on the cavity side sealing surface, thereby cutting off the flow passage behind the valve and the flow passage in front of the valve and the valve cavity where the valve core is located. However, under the action of the balance hole on the valve core, the valve cavity where the valve core is located is in communication with the flow passage in front of the valve, thereby guiding the fluid medium in the flow passage in front of the valve to the rear end of the throttling port, so that the pressure at the front end of the throttling port and the pressure at the rear end of the throttling port tend to be balanced, realizing differential pressure self-balancing regulation, i.e. full differential pressure (0~PN) operation, thereby completely solving the technical problem of small allowable working differential pressure of the traditional single seat regulating valve, and not being affected by the temperature and impurities contained in the fluid medium.

[0170] Embodiment 7

[0171] The other contents of this embodiment are the same as those of Embodiment 6, except that:

[0172] The inner edge of the top of the valve seat is a bevel structure, which constitutes the seat side sealing surface of the valve seat for cooperating with the valve core.

[0173] Embodiment 8

[0174] The other contents of this embodiment are the same as those of Embodiment 6, except that:

[0175] The inner edge of the bottom of the step structure of the inner periphery of the guide cylinder is a bevel structure, which constitutes the cavity side sealing surface.

[0176] The above embodiments are only used to illustrate the present application, but not to limit it;

[0177] Although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that the specific technical solutions in the above embodiments can be modified, or some technical features can be replaced by equivalents, for example, the outer convex height of the shoulder structure of the upper part of the valve core is 5mm or 7mm (correspondingly, the radial concave of the step structure of the pressure cage / guide cylinder is 5mm or 7mm), and these modifications or replacements do not make the essence of the corresponding technical solution deviate from the spirit and scope of the present application.

Claims

1. A differential pressure self-balancing single seat regulating valve, comprising a valve seat (2) and a valve core (3) arranged in a valve cavity of a valve body (1); the valve seat (2) is fixed on a throttling opening in the valve cavity, and the valve seat (2) has a seat side sealing surface (21) matched with the valve core (3); the valve core (3) can be lifted / descended in the valve cavity above the valve seat (2) through a valve rod (4), the bottom of the valve core (3) has a throttling curved surface matched with the valve seat (2), and the throttling curved surface has a core side lower sealing surface (33) matched with the seat side sealing surface (21), when the valve core (3) is lowered to the lowest position in the valve cavity, the core side lower sealing surface (33) is seated on the seat side sealing surface (21) to realize a hard contact sealing fit, thereby cutting off a valve front flow passage (11) in the valve body (1) and a valve rear flow passage (12); a balance hole (31) is arranged between the top surface and the throttling curved surface of the valve core (3), and the balance hole (31) can guide fluid medium in the valve front flow passage (11) into the valve cavity; characterized in that: the upper part of the valve core (3) has a circumferential outward convex shoulder structure, the bottom edge of the shoulder structure has a core side upper sealing surface (32), and the core side upper sealing surface (32) is a slope surface structure / curved surface structure of a slope transition between the outer edge of the shoulder structure and the body of the valve core (3); the valve cavity has a circumferential inward concave step structure in the area above the valve rear flow passage (12), and the step transition of the step structure has a cavity side sealing surface matched with the core side upper sealing surface (32); when the valve core (3) is lowered to the lowest position in the valve cavity, the core side upper sealing surface (32) is seated on the cavity side sealing surface to realize a hard contact sealing fit, thereby cutting off the valve cavity where the valve core (3) is located and the valve rear flow passage (12); the middle part of the valve core (3) has a circumferential inward concave flow expansion ring groove (34); when the valve core (3) is lowered to the lowest position in the valve cavity, the height position of the flow expansion ring groove (34) is within the coverage range of the upstream end of the valve rear flow passage (12); when the valve core (3) is lifted to the highest position in the valve cavity, the height position of the flow expansion ring groove (34) is within the coverage range of the upstream end of the valve rear flow passage (12).

2. The differential pressure self-balancing single seat regulating valve according to claim 1, characterized in that: the outward convex height of the shoulder structure at the upper part of the valve core (3) is less than or equal to 8 mm.

3. The differential pressure self-balancing single seat regulating valve according to claim 1, characterized in that: a pressure cage (6) is further arranged in the valve cavity of the valve body (1), the bottom of the pressure cage (6) abuts against the top of the valve seat (2), and the top of the pressure cage (6) abuts against the bottom of a valve cover (5) connected to the valve body (1); a plurality of flow channels (64) capable of connecting the valve cavity where the valve core (3) is located and the valve rear flow passage (12) are arranged in the circumference of the pressure cage (6), and the total flow area of the flow channels (64) is at least equal to the flow area of the valve seat (2) under the full opening state of the valve core (3). The cavity side sealing surface is shaped as a circumferential concave step structure on the inner wall of the pressure cage (6) above the flow channel (64).

4. The self-balanced single-seat control valve according to claim 3, wherein: The pressure cage (6) has an annular bottom beam (61), an annular upper beam (62), and at least two vertical columns (63) arranged at intervals around the circumference between the bottom beam (61) and the upper beam (62), and the flow channel (64) is formed between adjacent vertical columns (63) between the bottom beam (61) and the upper beam (62); The bottom edge of the bottom beam (61) is used to abut against the valve seat (2); The top edge of the upper beam (62) is used to abut against the valve cover (5).

5. The self-balanced single-seat control valve according to claim 4, wherein: The vertical column (63) of the pressure cage (6) has a rounded corner structure.

6. The self-balanced single-seat control valve according to claim 3 or 4, wherein: The bottom of the pressure cage (6) is shaped as a step structure with the outer edge outwardly convex downward; The top of the valve seat (2) is shaped as a step structure with the outer edge inwardly concave downward; The bottom of the pressure cage (6) and the top of the valve seat (2) are abutted and sealed in a concave-convex stop structure.

7. The self-balanced single-seat control valve according to claim 3 or 4, wherein: The top of the pressure cage (6) is shaped as a step structure with the inner edge outwardly convex upward; The bottom of the valve cover (5) used to cooperate with the area of the pressure cage (6) is shaped as a step structure with the outer edge outwardly convex downward; The top of the pressure cage (6) and the bottom of the valve cover (5) are abutted and sealed in a concave-convex stop structure.

8. The self-balanced single-seat control valve according to claim 1, 2 or 3, wherein: The valve core (3) is a hollow core structure having a cylindrical segment at the upper part and a curved housing segment at the lower part, and the inner space of the cylindrical segment and the inner space of the curved housing segment are in an up-down through structure; The valve core (3) has an inner folded valve rod seat at the top of the cylindrical segment, a connection structure of the valve rod (4) is arranged at the center of the valve rod seat, and the outer circumference of the valve rod seat is composed of a plurality of through holes arranged at intervals around the circumference to form a hollow structure; The shoulder structure and the core side upper sealing surface (32) of the valve core (3) are shaped at the upper part of the cylindrical segment; The center of the curved housing segment is provided with a balance hole (31) connected to the upper inner space, and the balance hole (31) is coaxially arranged with the valve rod connection structure on the cylindrical segment; The core side lower sealing surface (33) of the valve core (3) is shaped at the upper part of the curved housing segment.

9. The self-balanced single-seat control valve according to claim 1, 2 or 3, wherein: The valve core (3) is a solid core structure having a cylindrical segment at the upper part and a curved segment at the lower part; The top center of the cylindrical segment is provided with a connection structure of the valve rod (4), and the shoulder structure and the core side upper sealing surface (32) of the valve core (3) are shaped at the upper part of the cylindrical segment; The core side lower sealing surface (33) of the valve core (3) is formed at the upper part of the curved section; The balance hole (31) formed in the valve core (3) has two hole sections arranged in upper and lower positions; The first hole section of the balance hole (31) is vertically formed at the center of the curved section, and the forming position of the first hole section of the balance hole (31) on the curved section is coaxially arranged with the forming position of the valve rod connecting structure on the cylindrical section; The second hole section of the balance hole (31) is at least two inclined holes formed obliquely on the cylindrical section, the upper end of each inclined hole is at the outer periphery of the valve rod connecting structure at the top of the cylindrical section, the lower end is communicated with the first hole section of the balance hole (31), and the inclined holes are rotationally symmetrically formed on the cylindrical section with the axial direction of the valve rod connecting structure as the center.

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