Pilot balance type large-caliber ultrahigh pressure control valve

Abstract

The invention relates to the technical field of valves, in particular to a pilot balance type large-caliber ultrahigh pressure control valve. The valve 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, and an integral valve rod core assembly, a valve seat and a valve cage which are coaxial with one another are arranged in an inner cavity defined by the valve body and the valve cover; the valve seat tightly abuts against the valve body and the valve deck through a fastener and is sealed, and the valve cage is fixed in the valve body. The lower portion of the integral valve rod core assembly is located in the valve cage, the integral valve rod core assembly and the valve cage can axially and relatively slide, and the upper end of the integral valve rod core assembly penetrates through an inner cavity of the valve body and is sealed through the ultrahigh-pressure packing assembly. The whole valve rod core assembly comprises a main valve core and a pilot valve rod core, when the valve is opened, the pilot valve rod core is opened firstly to achieve upstream and downstream pressure equalization of the main valve core, medium unbalanced force on the main valve core is eliminated, output force needed by model selection of an executing mechanism can be effectively reduced, and then cost is reduced; when the valve is fully closed, tight cutting-off between the main valve element and the valve seat is mainly achieved through medium unbalanced force, and the higher the pressure difference is, the better the sealing effect is.

Description

Technical Field

[0001] The invention relates to the technical field of valves, in particular to a pilot balanced large-diameter ultra-high pressure control valve. Background Art

[0002] Usually, control valves with operating pressure not less than 100MPa are called ultra-high pressure control valves. In recent years, with the development of ultra-high pressure technology, ultra-high pressure control valves have been widely used in the fields of polyethylene production, such as static pressure treatment, artificial crystal, powder metallurgy, food pressure processing, water jet cutting, and test equipment.

[0003] When the ultra-high pressure control valve is in operation, the ultra-high pressure medium inside stores huge energy. Once an accident occurs, it will be catastrophic, especially for large-diameter ultra-high pressure control valves. The opening and closing flexibility, sealing performance, structural reliability, etc. all determine the safety and quality of ultra-high pressure operation. Due to the large throat diameter of the valve seat, the valve core is subjected to a great unbalanced force of the medium under ultra-high pressure conditions. Even if hydraulic drive control is adopted, the outer dimensions of the actuator are also very large, which not only increases the cost, but also puts forward higher requirements on the valve installation space. At the same time, the required valve stem diameter is also large, and the sealing reliability of large-sized ultra-high pressure packing components is difficult to guarantee. The balanced valve core structure adopted by conventional control valves mainly realizes the equalization of the upstream and downstream pressure chambers of the valve core by setting a balanced sealing ring. However, under ultra-high pressure conditions, on the one hand, the balanced sealing ring is difficult to ensure the sealing effect due to its large size. On the other hand, the friction between the balanced sealing ring and the guide element is very large, and the balanced sealing ring wears very quickly, which can easily lead to the failure of the balanced sealing ring, and then the large-diameter ultra-high pressure control valve cannot be opened, causing great safety risks, so it needs to be solved urgently. Summary of the invention

[0004] In order to avoid and overcome the technical problems existing in the prior art, the present invention provides a reasonably structured and practical pilot-balanced large-diameter ultra-high-pressure control valve, which can adapt to ultra-high-pressure working conditions, effectively reduce the output force required for the selection of the actuator, and has flexible and reliable opening and closing, can achieve strict shutoff, and has good reliability.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A pilot-balanced large-bore ultra-high pressure control valve is provided with a whole valve stem core assembly, a valve seat, and a valve cage that are coaxial with each other in the inner cavity formed by the valve body and the valve cover. The upper and lower sides of the valve seat are tightly abutted against the valve body and the valve cover respectively through fasteners and sealed. The valve cage is installed in the valve body with no relative movement between them. One side of the main valve core of the whole valve stem core assembly is installed in the valve cage with axial sliding fit between them. The valve stem side of the whole valve stem core assembly passes through the inner cavity of the valve body and is sealed through an ultra-high pressure packing assembly. The actuator provides driving force to realize the axial relative movement between the whole valve stem core assembly and the valve seat.

[0007] Preferably, the whole valve stem core assembly includes a main valve core, an elastic element, a pilot valve stem core, a guide and flow-limiting plate, etc. The pilot valve stem core is installed in the inner cavity of the main valve core, and the guide and flow-limiting plate is installed at the upper end of the main valve core. The elastic element is installed between the pilot valve stem core and the lower end face of the inner cavity of the main valve core. The pilot valve stem core is in precise fit with the main valve core and can slide axially relative to each other for guiding. The pilot valve stem core is limited by the upper limit on the lower end face of the guide and flow-limiting plate, and the pilot valve stem core is limited by the lower limit on the bottom end face of the inner cavity of the main valve core.

[0008] Preferably, the upper part of the main valve core is cylindrical, and the lower part is provided with a conical main sealing surface that fits and seals with the sealing surface of the valve seat when the valve is fully closed. The inner cavity of the main valve core is a cylindrical counterbore, and the bottom end face of the cylindrical hole is provided with a pilot sealing surface and an axially penetrating through-hole. The axially penetrating through-hole connects the main sealing surface and the pilot sealing surface.

[0009] Preferably, the upper part of the pilot valve stem core is provided with a cylindrical valve stem, the middle part is provided with a heavy-duty guide post, and the lower part is provided with a cylindrical valve core. The diameters of the cylindrical valve core and the cylindrical valve stem are both smaller than that of the heavy-duty guide post. A number of axial pressure relief grooves are evenly arranged along the circumferential direction on the outer surface of the pilot heavy-duty guide post. The cross-section of the axial pressure relief groove can be set as a semi-circular shape, a V-shaped shape, a U-shaped shape or other special shapes, and the cross-sectional area remains unchanged along the axial direction. A number of radial pressure relief grooves are evenly arranged along the circumferential direction on the lower end face of the heavy-duty guide post. The cross-section of the radial pressure relief groove can be set as a semi-circular shape, a V-shaped shape, a U-shaped shape or other special shapes, and the cross-sectional area remains unchanged along the radial direction. The lower part of the cylindrical valve core is provided with a pilot sealing surface that fits and seals with the pilot sealing surface of the main valve core when the valve is fully closed.

[0010] Preferably, the guide and flow-limiting plate is a cylindrical barrel, and the lower end of the cylindrical barrel is provided with an annular groove. A number of axially penetrating holes are evenly arranged along the circumferential direction at the bottom of the annular groove.

[0011] Preferably, the outer cylindrical surface of the main spool and the inner cylindrical surface of the valve cage are in precise fit, and the radial fit clearance between the two is 0.04 - 0.06 mm on one side; the total flow area of the axial through-hole on the main spool, the total flow area of the axial pressure relief grooves on the pilot valve stem core, the total flow area of the radial pressure relief grooves, the throttling area when the pilot valve stem core is fully open, and the total flow area of the axial through-holes of the flow guiding and limiting plate. The minimum value of the above five areas is more than 10 times the area of the ring formed by the radial fit clearance between the main spool and the valve cage.

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

[0014] Preferably, the valve seat adopts a conical gasket, a lens gasket or other structural forms. The valve seat is axially provided with a through-hole, and a truncated conical sealing surface is arranged on the upper part of the through-hole.

[0015] Preferably, both the main spool and the pilot valve stem core are made of a die steel integral forging that takes into account both strength and toughness, and the surface can be subjected to surface hardening treatments such as WC infiltration, nitriding, surfacing of STL hard alloy, surfacing of WC, chromium plating, QPQ, etc.

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

[0017] 1. The present invention realizes the pressure equalization between the upstream pressure chamber and the downstream of the main spool through the pilot spool, eliminating the medium unbalanced force on the main spool. On the one hand, it greatly reduces the output force required for the actuator selection, thereby reducing the cost; on the other hand, the volume of the upstream pressure chamber of the main spool is small, and the pilot spool can quickly realize the pressure equalization between the upstream pressure chamber and the downstream of the main spool, and it opens smoothly and reliably under ultra-high pressure difference.

[0018] 2. The present invention adopts a medium flow direction structure of flowing in from the top and flowing out from the bottom. In the fully closed state, through the initial sealing pre-tightening force provided by the actuator and under the action of the medium unbalanced force, a tight cut-off between the main spool and the valve seat is realized, and the higher the pressure difference, the better the sealing effect; at the same time, the pilot balanced spool structure can effectively reduce the required diameter of the valve stem, which is more friendly to the realization of reliable sealing of ultra-high pressure packing.

[0019] 3. The present invention is very suitable for ultra-high pressure working conditions. By adopting a pilot valve core to replace the traditional balance seal, the problem that the balance seal wears out quickly under ultra-high pressure working conditions is effectively solved, and the inherent safety of large-diameter ultra-high pressure control valves is improved.

[0020] 4. In the present invention, heavy cylindrical guiding is adopted between the pilot valve stem core and the main valve core, and also between the main valve core and the valve cage, which can effectively suppress the vibration damage of the pilot valve stem core and the main valve core caused by ultra-high pressure and high-speed medium flow. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the overall structure of Embodiment 1.

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

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

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

[0025] Figure 5 It is a partial axonometric view of the pilot valve stem core in the structure of Embodiment 1.

[0026] Figure 6 It is an axonometric view of the flow guiding and limiting plate in the structure of Embodiment 1.

[0027] Figure 7 It is a partial schematic view when the pilot valve stem core is fully closed and the main valve core is fully closed in the structure of Embodiment 2.

[0028] Figure 8 It is a partial schematic view when the pilot valve stem core is fully closed and the main valve core is fully closed in the structure of Embodiment 3.

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

[0030] In the figure: 10, threaded flange; 20, valve cover; 20a, valve outlet; 30, valve cover pressing 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 post; 53f, valve stem; 54, flow guiding and limiting plate; 54a, groove; 54b, flow guiding 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 pressing ring; 100, packing compression nut; 110, bracket; 120, actuator. Specific embodiments

[0031] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0032] Embodiment 1:

[0033] As Figures 1 to 6 shown, a pilot balanced large-bore ultra-high pressure control valve mainly includes an actuator 120, a bracket 110, a packing compression nut 100, a packing pressing 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 pressing plate 30, a valve cover 20, a threaded flange 10, etc. arranged in sequence from top to bottom. The valve cage 70 is in interference fit with the inner cavity of the valve body 60 coaxially. The upper end face of the valve cage 70 abuts against the inner cavity end face of the valve body 60. A tapered gasket sealing structure is adopted between the valve seat 40, the valve body 60 and the valve cover 20, and sufficient pre-tightening force is provided through bolt connection. The upper and lower tapered sealing surfaces of the valve seat 40 tightly abut against the sealing edges of the valve body 60 and the valve cover 20 respectively to achieve reliable ultra-high pressure static sealing and prevent ultra-high pressure medium from leaking. The outer shape of the valve body is approximately a hexahedron. The valve body and the valve cover are made of Cr-Ni-Mo-V high-strength low-alloy steel integral forgings, are connected to the ultra-high pressure pipeline through a threaded flange, and are sealed through a tapered gasket.

[0034] The valve seat 40, the integral valve stem core assembly 50, the valve cage 70, and the ultra-high pressure packing assembly 80 are coaxial with each other. The packing gland of the valve stem 53f and the valve body 60 realizes ultra-high pressure dynamic and static seals through the ultra-high pressure packing assembly 80 to prevent the leakage of ultra-high pressure media. The packing compression nut 100 is threadedly connected to the valve body 60, and the axial force is transmitted through the packing gland 90 to provide the initial pre-tightening force required for the seal of the ultra-high pressure packing assembly 80. The ultra-high pressure packing assembly 80 adopts a method of alternately arranging polymer V-shaped packings and copper alloy spacer rings, and realizes self-tightening seals through ultra-high pressure media.

[0035] The actuator 120 drives the integral valve stem core assembly 50 to move axially relative to the valve seat 40 through the valve stem 53f. Heavy-duty guide columns 53e are provided on the pilot valve stem core 53 to achieve precise sliding fit guidance with the inner cylindrical surface of the main valve core 51; the outer cylindrical surface of the main valve core 51 and the inner cylindrical surface of the valve cage 70 achieve precise sliding fit guidance.

[0036] As Figure 2 shown, by providing sufficient driving force through the actuator 120 to overcome the medium unbalanced force, packing friction force, and elastic force of the elastic element 52 acting on the pilot valve stem core 53, the pilot valve stem core sealing surface 53a is in full contact with the pilot sealing surface 51c of the main valve core and realizes sealing; at this time, the driving force provided by the actuator 120 transmitted through the pilot valve stem core 53 causes the main sealing surface 51a of the main valve core to contact the valve seat sealing surface 40a and realize initial sealing, and realizes a tight cut-off between the main valve core 51 and the valve seat 40 under the action of the medium unbalanced force to prevent the leakage of ultra-high pressure media. The main valve core 51 and the pilot valve stem core 53 are made of 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 surfacing with STL hard alloy to ensure reliable long-term use.

[0037] As Figure 3 shown, when the actuator 120 lifts the valve stem 53f, under the action of the medium unbalanced force and the elastic force of the elastic element 52 acting on the pilot valve stem core 53, the pilot valve stem core sealing surface 53a quickly disengages from contact with the pilot sealing surface 51c of the main valve core until the upper end face of the pilot valve stem core 53 contacts the limit end face 54c provided on the flow guiding limit plate 54. At this time, the ultra-high pressure source in the upstream pressure chamber 70a of the main valve core 51 is discharged to the downstream of the main valve core 51 through the flow guiding hole 54b provided on the flow guiding limit 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 equal pressure state is reached, and the medium unbalanced force acting on the main valve core 51 is eliminated. Under the action of the pilot valve stem core 53, the main sealing surface 51a of the main valve core disengages from contact with the valve seat sealing surface 40a until it reaches the fully open state as Figure 4 shown. The principle of the process of the valve from fully open to fully closed is vice versa.

[0038] In this embodiment, the outer cylindrical surface of the main spool 51 and the inner cylindrical surface of the valve cage 70 are in precise fit, and the radial fit clearance between the two is 0.04 mm on each side. The total cross-sectional area of the flow guiding holes 55b on the flow guiding and limiting plate 55, the total cross-sectional area of the axial pressure relief grooves 53d on the pilot valve stem core 53, the total cross-sectional area of the radial pressure relief grooves 53c, the throttling area when the pilot valve stem core 53 is fully open, and the cross-sectional area of the balance holes 51b on the main spool 51. The minimum value among the above five areas is 15 times the area of the ring formed by the radial fit clearance between the main spool 51 and the valve cage 70. Thus, the pressure relief rate from the upstream pressure chamber 70a to the downstream, i.e., the valve outlet 20a, is much faster than the pressure inlet rate from the valve inlet 60a to the upstream pressure chamber 70a, so as to quickly achieve pressure equalization between the upstream pressure chamber 70a of the main spool 51 and the downstream, effectively ensuring the smooth and reliable opening of the pilot balanced control valve under ultra-high pressure difference.

[0039] Embodiment 2:

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

[0041] Embodiment 3:

[0042] As Figure 8 and Figure 9 shown, the difference between this embodiment and Embodiment 1 is that in Embodiment 1, 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 spool 51 are in the form of planar hard seal, while in this embodiment, 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 spool 51 are in the form of conical hard seal.

[0043] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered within the protection scope of the present invention.

Claims

1. A pilot-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: An integral valve stem core assembly (50), a valve seat (40), and a valve cage (70) which are coaxial with each other are arranged in the inner cavity surrounded by the valve body (60) and the valve cover (20); the valve seat (40) is tightly pressed against the valve body (60) and the valve cover (20) by fasteners and sealed; the valve cage (70) is installed in the valve body, and the two do not move relative to each other; 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 the 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), and 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 attached and sealed, and at the same time, the main sealing surface (51a) and the sealing surface (40a) provided on the valve seat (40) are tightly attached and sealed; when the valve is opened, the pilot sealing surface (51c) and the sealing surface (53a) are first separated from each other, and then the main sealing surface (51a) and the sealing surface (40a) are separated from each other.

2. A pilot-balanced large-diameter ultra-high-pressure control valve according to claim 1, characterized in that: The integral valve stem core assembly (50) comprises the main valve core (51), an elastic element (52), the pilot valve stem core (53) and a guide limit plate (54); the pilot valve stem core (53) is coaxially mounted in the inner cavity of the main valve core (51), the guide limit plate (54) is mounted on the upper end surface of the main valve core (51) via fasteners, and the elastic element (52) is mounted 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) are axially slidable relative to each other, and the pilot valve stem core (53) is axially upper-limited by the lower end surface of the guide limit plate (54), and is lower-limited by the pilot sealing surface (51c).

3. A pilot-balanced large-diameter ultra-high-pressure control valve according to claim 2, characterized in that: The upper part of the main valve core (51) is cylindrical, and the lower part is provided with the conical main sealing surface (51a), the end surface of the inner cavity of the columnar counterbore is provided with the pilot sealing surface (51c), and the lower part of the inner cavity of the columnar counterbore is provided with a through balancing hole (51b), and the balancing hole (51b) connects the main sealing surface (51a) and the pilot sealing surface (51c); the main valve core (51) and the valve cage (70) are precisely matched and can slide relative to each other in the axial direction.

4. A pilot-balanced large-diameter ultra-high-pressure control valve according to claim 2, characterized in that: The pilot valve stem core (53) is provided with a columnar valve stem (53f) at the upper part, a heavy-duty guide column (53e) at the middle part, and a columnar valve core (53b) at the lower part; the diameters of the valve core (53b) and the valve stem (53f) are both smaller than the heavy-duty guide column (53e); the sealing surface (53a) is provided at the lower part of the valve core (53b); a plurality of axial pressure relief grooves (53d) are evenly arranged along the circumferential direction on the outer surface of the heavy-duty guide column (53e), and a plurality of radial pressure relief grooves (53c) are evenly arranged along the circumferential direction on the lower end surface.

5. The pilot-balanced large-diameter ultra-high-pressure control valve according to claim 2, characterized in that: The flow guide and limiting plate (54) is a cylindrical body, with a circular ring-shaped groove (54a) arranged at the bottom, and a plurality of axially penetrating flow guide holes (54b) are evenly arranged at the bottom of the groove (54a) along the axial direction.

6. A pilot-balanced large-diameter ultra-high-pressure control valve according to any one of claims 2 to 5, characterized in that: The radial clearance between the main valve core (51) and the valve cage (70) is 0.04 to 0.06 mm on one side; the minimum value of the flow area of ​​the balancing 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 area of ​​the annular ring formed by the radial clearance between the main valve core (51) and the valve cage (70).

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

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

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

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

Images