A pilot balanced large-diameter ultrahigh pressure control valve

Abstract

The present application relates to the technical field of valve, in particular to a pilot balanced large-diameter superhigh pressure control valve. The present application comprises a valve body and a valve cover, the valve body is provided with a valve inlet, the valve cover is provided with a valve outlet, an integral valve stem core assembly, a valve seat and a valve cage are coaxially arranged in the inner cavity surrounded by the valve body and the valve cover; the valve seat is tightly abutted on the valve body and the valve cover and sealed by fasteners, the valve cage is fixed in the valve body; the lower part of the integral valve stem core assembly is located in the valve cage, and the two can axially slide relative to each other, the upper end of the integral valve stem core assembly passes through the inner cavity of the valve body and is sealed by a superhigh pressure packing assembly; the integral valve stem core assembly comprises a main valve core and a pilot valve stem core; when the present application is opened, the pressure of the upstream and downstream of the main valve core is balanced by first opening the pilot valve stem core, the unbalanced force of the medium on the main valve core is eliminated, the output force required for the selection of the actuator can be effectively reduced, and the cost is further reduced; when the present application is fully closed, the tight cut-off between the main valve core and the valve seat is mainly realized by the unbalanced force of the medium, and the higher the pressure difference is, the better the sealing effect is.

Description

Technical Field

[0001] This invention relates to the field of valve technology, specifically a pilot-operated balanced large-diameter ultra-high pressure control valve. Background Technology

[0002] Control valves with an operating pressure of not less than 100 MPa are generally referred to as ultra-high pressure control valves. In recent years, with the development of ultra-high pressure technology, ultra-high pressure control valves have been increasingly widely used in fields such as isostatic pressing in polyethylene production, artificial crystal, powder metallurgy, food pressure processing, waterjet cutting, and testing equipment.

[0003] When ultra-high pressure control valves are in operation, the internal ultra-high pressure medium stores enormous energy. An accident could be catastrophic, especially for large-diameter ultra-high pressure control valves. Opening and closing flexibility, sealing performance, and structural reliability all determine the safety and quality of ultra-high pressure operation. Due to their large seat throat diameter, large-diameter ultra-high pressure control valves experience extremely high unbalanced forces from the medium under ultra-high pressure conditions. Even with hydraulic drive control, the actuator's dimensions are very large, increasing costs and placing high demands on valve installation space. Simultaneously, the required valve stem diameter is also large, making it difficult to guarantee the sealing reliability of large-sized ultra-high pressure packing assemblies. Conventional control valves use a balanced valve core structure, primarily achieving pressure equalization between the upstream and downstream pressure chambers of the valve core through a balancing sealing ring. However, under ultra-high pressure conditions, on the one hand, the large size of the balancing sealing ring makes it difficult to guarantee a sealing effect; on the other hand, the friction between the balancing sealing ring and the guide element is extremely high, leading to rapid wear of the balancing sealing ring and making it prone to failure. This can prevent the large-diameter ultra-high pressure control valve from opening, posing a significant safety risk, thus requiring urgent solutions. Summary of the Invention

[0004] To avoid and overcome the technical problems existing in the prior art, the present invention provides a pilot-operated balanced large-diameter ultra-high pressure control valve with a reasonable structure and practicality. It can adapt to ultra-high pressure working conditions, effectively reduce the output force required for actuator selection, and is flexible and reliable in opening and closing. It can achieve tight shut-off and has good reliability.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A pilot-operated balanced large-diameter ultra-high pressure control valve comprises an integral valve stem core assembly, a valve seat, and a valve cage, all coaxially arranged within an inner cavity formed by a valve body and a valve cover. The upper and lower sides of the valve seat are tightly abutted and sealed against the valve body and valve cover respectively by fasteners. The valve cage is installed within the valve body, with no relative movement between the two. One side of the main valve core of the integral valve stem core assembly is installed within the valve cage, with axial sliding engagement between the two. The valve stem side of the integral valve stem core assembly passes through the inner cavity of the valve body and is sealed by an ultra-high pressure packing assembly. An actuator provides driving force to achieve axial relative movement between the integral valve stem core assembly and the valve seat.

[0007] Preferably, the integral valve stem assembly includes a main valve stem, an elastic element, a pilot valve stem, a guide flow restrictor, etc.; the pilot valve stem is installed in the inner cavity of the main valve stem, and the guide flow restrictor is installed on the upper end of the main valve stem; the elastic element is installed between the pilot valve stem and the lower end face of the inner cavity of the main valve stem; the pilot valve stem and the main valve stem are precisely fitted and axially slidably guided; the pilot valve stem is limited by the lower end face of the guide flow restrictor and the pilot valve stem is limited by the bottom end face of the inner cavity of the main valve stem.

[0008] Preferably, the upper part of the main valve core is cylindrical, and the lower part is provided with a conical main sealing surface. When the valve is fully closed, it fits and seals with the sealing surface of the valve seat. The inner cavity of the main valve core is a columnar countersunk hole. The bottom end face of the columnar hole is provided with a pilot sealing surface and an axial through hole. The axial through hole connects the main sealing surface and the pilot sealing surface.

[0009] Preferably, the pilot valve stem core has a columnar valve stem at the upper part, a heavy-duty guide column in the middle, and a columnar valve core at the lower part. The diameters of the columnar valve core and the columnar valve stem are both smaller than those of the heavy-duty guide column. A plurality of axial pressure relief grooves are uniformly arranged circumferentially on the outer surface of the pilot heavy-duty guide column. The cross-section of the axial pressure relief grooves can be semi-circular, V-shaped, U-shaped, or other irregular shapes, and the cross-sectional area remains constant along the axial direction. A plurality of radial pressure relief grooves are uniformly arranged circumferentially on the lower end face of the heavy-duty guide column. The cross-section of the radial pressure relief grooves can be semi-circular, V-shaped, U-shaped, or other irregular shapes, and the cross-sectional area remains constant along the radial direction. A pilot sealing surface is provided at the lower part of the columnar valve core, which seals against the pilot sealing surface of the main valve core when the valve is fully closed.

[0010] Preferably, the flow guiding and limiting plate is a cylindrical body, and an annular groove is provided at the lower end of the cylindrical body, with a plurality of axial through holes evenly provided circumferentially at the bottom of the annular groove.

[0011] Preferably, the outer cylindrical surface of the main valve core and the inner cylindrical surface of the valve cage are precisely fitted, with a radial fit clearance of 0.04 to 0.06 mm on each side; the minimum value of the following five areas is more than 10 times the area of ​​the annulus formed by the radial fit clearance between the main valve core and the valve cage: the axial through-hole flow area on the main valve core, the total axial pressure relief groove flow area on the pilot valve stem core, the total radial pressure relief groove flow area, the throttling area when the pilot valve stem core is fully open, and the total flow area of ​​the axial through-hole of the flow guide and limiting plate.

[0012] Preferably, the valve body has a square shape and is made of high-strength steel integral forging. The valve body is provided with a transverse hole for forming a fluid inlet. The valve body inlet end face is provided with a threaded bolt hole and is connected to the ultra-high pressure pipeline through a threaded flange, and is sealed with a lens gasket or a conical gasket.

[0013] Preferably, the valve cover is provided with an axial through hole for forming a fluid outlet, the valve cover is made of high-strength steel integral forging, the valve cover outlet is connected to the ultra-high pressure pipeline through a threaded flange, and is sealed with a lens gasket or a conical gasket.

[0014] Preferably, the valve seat adopts a conical pad, lens pad or other structural form, the valve seat is provided with a through hole in the axial direction, and a truncated conical sealing surface is provided on the upper part of the through hole.

[0015] Preferably, both the main valve core and the pilot valve stem core are manufactured from integral forgings of mold steel that balance strength and toughness, and their surfaces can be subjected to surface hardening treatments such as WC diffusion, nitriding, STL hard alloy overlay welding, WC overlay welding, chrome plating, and QPQ.

[0016] Compared with the prior art, the beneficial effects of the present invention are:

[0017] 1. This invention achieves pressure equalization between the upstream and downstream pressure chambers of the main valve core through a pilot valve core, eliminating the unbalanced force of the medium on the main valve core. On the one hand, this greatly reduces the output force required for actuator selection, thereby reducing costs; on the other hand, the upstream pressure chamber of the main valve core has a small volume, allowing the pilot valve core to quickly achieve pressure equalization between the upstream and downstream pressure chambers of the main valve core, resulting in smooth and reliable opening under ultra-high pressure differentials.

[0018] 2. This invention adopts a medium flow structure with top inlet and bottom outlet. In the fully closed state, the initial sealing pre-tightening force provided by the actuator, under the action of the unbalanced force of the medium, achieves a tight seal between the main valve core and the valve seat. The higher the pressure difference, the better the sealing effect. At the same time, the pilot balanced valve core structure can effectively reduce the required diameter of the valve stem, thus making it more friendly to the realization of reliable sealing of ultra-high pressure packing.

[0019] 3. This invention is very suitable for ultra-high pressure conditions. By using a pilot valve core to replace the traditional balance seal, it effectively solves the problem of rapid wear and failure of the balance seal under ultra-high pressure conditions, and improves the inherent safety of large-diameter ultra-high pressure control valves.

[0020] 4. This invention effectively suppresses vibration damage to the pilot valve stem and main valve core caused by ultra-high pressure and high speed medium flow by using heavy-duty cylindrical guide between the pilot valve stem core and the main valve core, as well as between the main valve core and the valve cage. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure of Example 1.

[0022] Figure 2 This is a partial enlarged view of the structure in Example 1 when the pilot valve stem is fully closed and the main valve is fully closed.

[0023] Figure 3 This is a partial enlarged view of the structure in Example 1 when the pilot valve stem is fully open and the main valve is fully closed.

[0024] Figure 4 This is a partial enlarged view of the structure in Example 1 when the pilot valve stem is fully open and the main valve is fully open.

[0025] Figure 5 This is a partial isometric view of the pilot valve stem core in the structure of Example 1.

[0026] Figure 6 This is an isometric view of the flow guiding and limiting plate in the structure of Example 1.

[0027] Figure 7 This is a partial schematic diagram of the structure in Example 2 when the pilot valve stem is fully closed and the main valve is fully closed.

[0028] Figure 8 This is a partial schematic diagram of the structure in Example 3 when the pilot valve stem is fully closed and the main valve is fully closed.

[0029] Figure 9 This is a partial isometric view of the pilot valve stem core in Embodiment 3 of the present invention.

[0030] In the diagram: 10, threaded flange; 20, valve cover; 20a, valve outlet; 30, valve cover pressure plate; 40, valve seat; 40a, valve seat sealing surface; 50, integral valve stem core assembly; 51, main valve core; 51a, main sealing surface; 51b, balance hole; 51c, pilot sealing surface; 52, elastic element; 53, pilot valve stem core; 53a, sealing surface; 53b, valve core; 53c, radial pressure relief groove; 53d, axial pressure relief groove; 53e, heavy-duty guide column; 53f, valve stem; 54, flow guide and limiting plate; 54a, groove; 54b, flow guide hole; 54c, limiting end face; 60, valve body; 60a, valve inlet; 70, valve cage; 70a, upstream pressure chamber; 80, ultra-high pressure packing assembly; 90, packing pressure ring; 100, packing clamping nut; 110, bracket; 120, actuator. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] Example 1:

[0033] like Figures 1-6 As shown, a pilot-operated balanced large-diameter ultra-high pressure control valve mainly includes, from top to bottom, an actuator 120, a bracket 110, a packing clamping nut 100, a packing ring 90, an ultra-high pressure packing assembly 80, a valve cage 70, a valve body 60, an integral valve stem core assembly 50, a valve seat 40, a valve cover pressure plate 30, a valve cover 20, and a threaded flange 10. The valve cage 70 is coaxially interference-fitted with the inner cavity of the valve body 60, and the upper end face of the valve cage 70 abuts against the end face of the inner cavity of the valve body 60. The valve seat 40 adopts a conical gasket sealing structure with the valve body 60 and the valve cover 20. Sufficient preload is provided by bolt connection. The upper and lower conical sealing surfaces of the valve seat 40 tightly abut against the sealing corners of the valve body 60 and the valve cover 20, respectively, to achieve reliable ultra-high pressure static sealing and prevent leakage of ultra-high pressure medium. The valve body is approximately hexahedral in shape. The valve body and valve cover are made of Cr-Ni-Mo-V high-strength low-alloy steel integral forgings. They are connected to the ultra-high pressure pipeline through threaded flanges and sealed with tapered gaskets.

[0034] The valve seat 40, integral valve stem core assembly 50, valve cage 70, and ultra-high pressure packing assembly 80 are coaxial with each other. The packing gland of the valve stem 53f and valve body 60 achieves ultra-high pressure dynamic and static sealing through the ultra-high pressure packing assembly 80 to prevent leakage of ultra-high pressure medium. The packing compression nut 100 is threadedly connected to the valve body 60, and transmits axial force through the packing pressure ring 90 to provide the initial preload required for sealing of the ultra-high pressure packing assembly 80. The ultra-high pressure packing assembly 80 adopts an alternating arrangement of polymer V-shaped packing and copper alloy spacer rings to achieve self-tightening sealing through ultra-high pressure medium.

[0035] The actuator 120 drives the integral valve stem core assembly 50 and the valve seat 40 to move axially relative to each other via the valve stem 53f. The pilot valve stem core 53 is provided with a heavy-duty guide post 53e, which achieves a precise sliding fit with the inner cylindrical surface of the main valve core 51; the outer cylindrical surface of the main valve core 51 achieves a precise sliding fit with the inner cylindrical surface of the valve cage 70.

[0036] like Figure 2 As shown, the actuator 120 provides sufficient driving force to overcome the unbalanced force of the medium, the frictional force of the packing, and the elastic force of the elastic element 52 on the pilot valve stem core 53. The pilot valve stem core sealing surface 53a is in complete contact with the main valve core pilot sealing surface 51c and achieves a seal. At this time, through the driving force provided by the actuator 120 transmitted by the pilot valve stem core 53, the main valve core main sealing surface 51a is in contact with the valve seat sealing surface 40a and achieves an initial seal. Under the action of the unbalanced force of the medium, a tight seal is achieved between the main valve core 51 and the valve seat 40, preventing internal leakage of the ultra-high pressure medium. The main valve core 51 and the pilot valve stem core 53 are manufactured as integral forgings of hot-work die steel. The surface of the valve stem 53f is chrome-plated, and the outer surface of the main valve core 51 and the remaining surfaces of the pilot valve stem core 53 are PTA plasma-welded with STL hard alloy to ensure long-term reliable use.

[0037] like Figure 3 As shown, the actuator 120 lifts the valve stem 53f. Under the action of the unbalanced force of the medium on the pilot valve stem core 53 and the elastic force of the elastic element 52, the pilot valve stem core sealing surface 53a quickly disengages from the main valve core pilot sealing surface 51c until the upper end face of the pilot valve stem core 53 contacts the limiting end face 54c provided on the flow limiting plate 54. At this time, the ultra-high pressure source in the upstream pressure chamber 70a of the main valve core 51 releases pressure downstream of the main valve core 51 through the flow guiding hole 54b provided on the flow limiting plate 54, the semi-circular axial pressure relief groove 53d and the semi-circular radial pressure relief groove 53c provided on the pilot valve stem core 53, and the balance hole 51b provided on the main valve core 51, until the pressure is equalized. The unbalanced force of the medium on the main valve core 51 is eliminated. Under the action of the pilot valve stem core 53, the main valve core sealing surface 51a disengages from the valve seat sealing surface 40a until the pressure is equalized. Figure 4 The diagram shows the fully open state. This illustrates the principle of the valve's process from fully open to fully closed, and vice versa.

[0038] In this embodiment, the outer cylindrical surface of the main valve core 51 and the inner cylindrical surface of the valve cage 70 are precisely fitted, with a radial fit clearance of 0.04mm on each side. The minimum value among the following five areas—the total cross-sectional area of ​​the guide hole 55b on the guide limiting plate 55, the total cross-sectional area of ​​the axial pressure relief groove 53d on the pilot valve stem core 53, the total cross-sectional area of ​​the radial pressure relief groove 53c, the throttling area of ​​the pilot valve stem core 53 when fully open, and the cross-sectional area of ​​the balance hole 51b on the main valve core 51—is 15 times the area of ​​the annulus formed by the radial fit clearance between the main valve core 51 and the valve cage 70. Therefore, the rate at which the pressure in the upstream pressure chamber 70a is released downstream (towards the valve outlet 20a) is much faster than the rate at which pressure is introduced from the valve inlet 60a into the upstream pressure chamber 70a, quickly achieving pressure equalization between the upstream and downstream pressure chambers of the main valve core 51. This effectively ensures the smooth and reliable opening of the pilot-operated balanced control valve under ultra-high pressure differential.

[0039] Example 2:

[0040] like Figure 7 As shown, the difference between this embodiment and embodiment 1 is that the elastic element 52 in embodiment 1 is a combined disc spring, while the elastic element 52 in this embodiment is a cylindrical helical compression spring.

[0041] Example 3:

[0042] like Figure 8 and Figure 9 As shown, the difference between this embodiment and embodiment 1 is that the sealing surface 53a provided at the lower part of the pilot valve stem core 53 and the pilot sealing surface 51c provided on the main valve core 51 in embodiment 1 are planar hard seals, while the sealing surface 53a provided at the lower part of the pilot valve stem core 53 and the pilot sealing surface 51c provided on the main valve core 51 in this embodiment are conical hard seals.

[0043] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A pilot-operated balanced large-diameter ultra-high pressure control valve, comprising a valve body (60) and a valve cover (20), wherein the valve body (60) is provided with a valve inlet (60a) and the valve cover (20) is provided with a valve outlet (20a), characterized in that: The inner cavity formed by the valve body (60) and the valve cover (20) is provided with an integral valve stem core assembly (50), a valve seat (40), and a valve cage (70) that are coaxial with each other. The valve seat (40) is tightly abutted against the valve body (60) and the valve cover (20) by fasteners and is sealed. The valve cage (70) is installed in the valve body and there is no relative movement between the two. The lower part of the integral valve stem core assembly (50) is located in the valve cage (70) and the two can slide axially relative to each other. The upper part of the integral valve stem core assembly (50) passes through the inner cavity of the valve body (60) and is sealed by an ultra-high pressure packing assembly (80). The integral valve stem core assembly (50) is provided with A main valve core (51) and a pilot valve stem core (53) are provided. The main valve core (51) is provided with a main sealing surface (51a) and a pilot sealing surface (51c). The pilot valve stem core (53) is provided with a sealing surface (53a). When the valve is fully closed, the pilot sealing surface (51c) and the sealing surface (53a) are tightly fitted and sealed. At the same time, the main sealing surface (51a) and the sealing surface (40a) provided on the valve seat (40) are tightly fitted and sealed. When the valve is opened, the pilot sealing surface (51c) and the sealing surface (53a) first disengage, and then the main sealing surface (51a) and the sealing surface (40a) disengage. The integral valve stem core assembly (50) includes the main valve core (51), an elastic element (52), the pilot valve stem core (53), and a flow limiting plate (54). The pilot valve stem core (53) is coaxially installed in the inner cavity of the main valve core (51). The flow limiting plate (54) is installed on the upper end face of the main valve core (51) by fasteners. The elastic element (52) is installed between the pilot valve stem core (53) and the pilot sealing surface (51c). The pilot valve stem core (53) and the main valve core (51) can slide relative to each other axially. The pilot valve stem core (53) is axially limited by the lower end face of the flow limiting plate (54) and lower limited by the pilot sealing surface (51c).

2. The pilot-operated balanced large-diameter ultra-high pressure control valve according to claim 1, characterized in that: The upper part of the main valve core (51) is cylindrical, and the lower part is provided with a conical main sealing surface (51a). The inner end face of the cylindrical countersunk hole is provided with the pilot sealing surface (51c). The lower part of the cylindrical countersunk hole is provided with a through balance hole (51b). The balance hole (51b) connects the main sealing surface (51a) and the pilot sealing surface (51c). The main valve core (51) is precisely fitted with the valve cage (70) and can slide relative to it axially.

3. The pilot-operated balanced large-diameter ultra-high pressure control valve according to claim 2, characterized in that: The pilot valve stem core (53) has a columnar valve stem (53f) at the top, a heavy-duty guide post (53e) in the middle, and a columnar valve core (53b) at the bottom; the diameters of the valve core (53b) and the valve stem (53f) are both smaller than the heavy-duty guide post (53e); the valve core (53b) has a sealing surface (53a) at the bottom; the heavy-duty guide post (53e) has a plurality of axial pressure relief grooves (53d) evenly arranged circumferentially on its outer surface, and a plurality of radial pressure relief grooves (53c) evenly arranged circumferentially on its lower end face.

4. The pilot-operated balanced large-diameter ultra-high pressure control valve according to claim 3, characterized in that: The flow guiding and limiting plate (54) is a cylindrical body with an annular groove (54a) at the bottom. Several axially penetrating flow guiding holes (54b) are uniformly arranged at the bottom of the groove (54a) along the axial direction.

5. A pilot-operated balanced large-diameter ultra-high pressure control valve according to claim 4, characterized in that: The radial fit clearance between the main valve core (51) and the valve cage (70) is 0.04~0.06mm on one side; the minimum value among the flow area of ​​the balance hole (51b), the total flow area of ​​the axial pressure relief groove (53d), the total flow area of ​​the radial pressure relief groove (53c), the rated throttling area of ​​the valve core (53b), and the total flow area of ​​the guide hole (54b) is more than 10 times the annular area formed by the radial fit clearance between the main valve core (51) and the valve cage (70).

6. A pilot-operated balanced large-diameter ultra-high pressure control valve according to claim 5, characterized in that: The cross-sections of the axial pressure relief groove (53d) and the radial pressure relief groove (53c) can be set as semi-circular, V-shaped or U-shaped, and the cross-sections remain unchanged along the axial and radial directions, respectively.

7. A pilot-operated balanced large-diameter ultra-high pressure control valve according to claim 1, characterized in that: The valve body (60) is a square shape and is made of high-strength steel integral forging. A valve inlet (60a) is set on one side of the transverse hole, and a wire bolt hole is set on the same side. It is bolted to the threaded flange (10) of the ultra-high pressure pipeline and sealed with a lens gasket or a conical gasket.

8. A pilot-operated balanced large-diameter ultra-high pressure control valve according to claim 1, characterized in that: The valve cover (20) is axially penetrating, and a valve outlet (20a) is provided at one end, which is bolted to the threaded flange (10) of the ultra-high pressure pipeline and sealed with a lens gasket or a conical gasket.

9. A pilot-operated balanced large-diameter ultra-high pressure control valve according to claim 8, characterized in that, The valve cover (20) is made of high-strength steel integral forging.

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