Pilot valve element capable of being opened quickly, reducing thrust and being low in leakage

Abstract

The utility model discloses a quick-opening, thrust-reducing and low-leakage pilot valve element which comprises a valve body (1), balance holes are formed in the valve body (1) in a circle around the valve body (1), and a through-flow hole is formed in the valve body (1). The balance hole is formed in the through-flow hole, the valve element (2) is installed in the balance hole, a gap formed between the valve element (2) and the balance hole is a flow area, one end of the valve element (2) is provided with a curved surface section (21), the curved surface section (21) is buckled into the through-flow hole, and the through-flow hole is sealed by the valve element (2). By improving the structure of the curved surface section of the valve core and milling a plurality of tangent planes at the two ends and in the middle of the curved surface section on the basis of retaining a sealing surface, the flow area of the valve core during opening is increased, and the problem that the flow area of a pre-starting valve core in the prior art is too small, so that quick balance cannot be realized is effectively solved; and the quick opening of the valve is realized.

Description

Technical Field

[0001] The utility model relates to a pilot valve spool, in particular to a pilot valve spool that can be quickly opened, reduce thrust, and have low leakage. Background Art

[0002] In the boiler or chemical industry, steam pressure reducing valves are indispensable valves, which are responsible for reducing steam pressure and regulating steam flow. In some special work positions, it is required that the valve be quickly opened from the fully closed state. At the same time, considering strength and cost, the thrust needs to be greatly reduced, and once the valve is fully closed, the leakage of the valve should be minimized as much as possible. However, there are not many valve structures that can meet all three requirements at present.

[0003] The medium of the steam pressure reducing valve is high-temperature and high-pressure steam. As is well known, the specific volume of steam is large and the density is small, that is, the volume of steam is larger than that of liquids such as water under the same mass. If a steam pressure reducing valve wants to meet the flow rate required by process parameters, it often needs to increase the flow area of the spool and valve seat. Once the size is increased, the problem of a sharp increase in thrust (deformation of P = F / S, that is, F = P×S) will be faced, and the actuator cannot quickly open the valve when facing such a high load (the electric actuator will be overloaded, and the cylinder or diaphragm of the pneumatic actuator will burst).

[0004] To solve the problem of excessive thrust, a balanced structure has been introduced in the industry, that is, balance holes are opened on a solid spool, and the two sides of the spool are designed, that is, the area of one side of the steam inlet is larger than that of the other side, that is, S1 > S2. Because balance holes are opened and the pressure on both sides is the same P1 = P2, so F1 = P1×S1 > F2 = P2×S2, and the actual load of the actuator is (F1 - F2) < F2, so as to reduce the thrust and achieve quick opening at the same time. However, this has led to a defect. When the valve is in the fully closed state, steam leaks into the valve body through the gap covered by the spool, and balance holes are opened in the valve body, so the steam leaks from the balance holes to the downstream pipeline. The consequence is that a large amount of steam leakage violates the process requirements, has potential safety and quality hazards, and the wasted steam causes property losses.

[0005] In summary, ordinary balanced structures can only meet quick opening and thrust reduction. They cannot meet the three requirements of quick opening, thrust reduction, and low leakage control at the same time.

[0006] Such as Figure 1 and Figure 2As shown in the figure, to solve the problem of excessive thrust, a balanced structure has been introduced in the industry, that is, balance holes are drilled in the solid valve core, and the two sides of the valve core are designed such that the area of the side where the steam inlet is located is larger than that of the other side, that is, S1 > S2. Because of the balance holes, the pressures on both sides are the same, P1 = P2, so F1 = P1×S1 > F2 = P2×S2, and the actual load of the actuator is (F1 - F2) < F2, thereby reducing the thrust and achieving quick opening at the same time. However, this has led to a defect. When the valve is in the fully closed state, steam leaks into the valve body through the gap covered by the valve core, and there are balance holes in the valve body, so the steam leaks from the balance holes to the downstream pipeline. The consequence is that the large amount of steam leakage violates the process requirements, has potential safety and quality hazards, and the wasted steam causes property losses.

[0007] Figure 1 In it, A1 is the balance hole, which can achieve quick balance, but the leakage amount cannot be controlled;

[0008] Figure 2 In it, the actual thrust of this structure is F1 - F2 < F2, achieving thrust reduction, but A2 is much smaller than A1, and the flow area is too small to achieve quick balance, that is, quick opening cannot be achieved.

[0009] In summary, the ordinary balanced type can only meet quick opening and thrust reduction. It cannot meet quick opening, thrust reduction, and low leakage control simultaneously. Summary of the Invention

[0010] To solve the above problems, the present utility model provides a pilot valve core that can achieve quick opening, thrust reduction, and low leakage. By milling the two ends and the middle of the curved surface of the valve core, retaining the sealing surface, and only expanding the flow area when it is opened, the deficiencies in the prior art can be effectively solved.

[0011] The present utility model is realized through the following technical solutions: A pilot valve core that can achieve quick opening, thrust reduction, and low leakage, comprising:

[0012] A valve body, around which a balance hole is provided in a circle, and a flow hole is provided inside the valve body;

[0013] A valve core, which is installed in the balance hole, and the gap formed between the valve core and the balance hole is the flow area. One end of the valve core has a curved surface section, and the curved surface section is buckled into the flow hole and the valve core seals the flow hole;

[0014] A valve stem, which extends into the valve body and is threadedly connected to the other end of the valve core;

[0015] A first cutting plane is opened in the middle of the curved surface section of the valve core, and a second cutting plane is opened perpendicular to the first cutting plane on both sides of the curved surface section. The flow area when the valve core is opened is enlarged through the first cutting plane and the cutting plane.

[0016] As a preferred technical solution, a sealing surface is provided at the junction of the valve core and the curved surface section. There is a sealing contact surface in the flow passage hole, and the valve core seals the flow passage hole through the sealing surface.

[0017] As a preferred technical solution, the bottom surface of the first cutting plane is an arc bottom surface R2, and the shortest straight-line distance from the center of the arc bottom surface R2 to the sealing surface is Z.

[0018] As a preferred technical solution, Z satisfies Z≥R2 + 0.1.

[0019] As a preferred technical solution, R2 satisfies R2≤(X - 10) / 2, where X is the maximum outer diameter of the curved surface section of the valve core.

[0020] As a preferred technical solution, one end face of the curved surface section has a chamfer R1, and R1 satisfies R1 = X / 5.

[0021] As a preferred technical solution, an angle B is formed between the curved surface section and the horizontal plane, and the angle B is 15 degrees - 45 degrees.

[0022] As a preferred technical solution, the thickness of the thinnest curved surface section between the two second cutting planes is W, and W≥10.

[0023] As a preferred technical solution, an arc section R4 is formed at the bottom position of each second cutting plane, and R4 satisfies R4≈3W / 4. The straight-line length of the arc section is Y.

[0024] The beneficial effects of the present utility model are as follows: Through the structural improvement of the curved surface section of the valve core, while retaining the sealing surface, multiple cutting planes are milled at both ends and in the middle of the curved surface section, thereby increasing the flow area when the valve core is opened, effectively solving the problem of inability to quickly balance caused by the too small flow area of the pre-opening valve core in the prior art, and realizing the quick opening of the valve. At the same time, this design retains the advantages of the balanced structure. While maintaining the pressure balance on both sides of the steam, the load of the actuator is reduced by reducing the thrust. In addition, by reasonably setting the positions and shapes of the first cutting plane and the second cutting plane, the present invention can effectively block the leakage of steam in the fully closed state, ensuring the low leakage performance of the valve, thereby meeting the three requirements of quick opening, thrust reduction, and low leakage of the steam pressure reducing valve in industry, and improving the safety, stability, and service life of the valve. Description of the Drawings

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0026] Figure 1 It is a schematic structural diagram of a structure with a balanced spool in the prior art;

[0027] Figure 2 It is a schematic structural diagram of a balanced spool with a pre-opening spool in the prior art;

[0028] Figure 3 It is a schematic overall cross-sectional view of the present invention;

[0029] Figure 4 It is a schematic three-dimensional cross-sectional view of the present invention;

[0030] Figure 5 It is a schematic structural diagram of the spool of the present invention;

[0031] Figure 6 It is a schematic diagram of the present invention Figure 1 ;

[0032] Figure 7 It is a schematic diagram of the present invention Figure 2 ;

[0033] Explanation of reference numerals:

[0034] 1. Valve body; 2. Spool; 3. Valve stem; 21. Curved surface section; 22. Sealing surface; 23. First cutting plane; 24. Second cutting plane. Detailed implementation manners

[0035] All features disclosed in this specification, or all steps in the disclosed methods or processes, except for mutually exclusive features and / or steps, can be combined in any way.

[0036] Any feature disclosed in this specification (including any additional claims, abstract, and drawings), unless specifically stated, can be replaced by other equivalent or similar-purpose alternative features. That is, unless specifically stated, each feature is only an example of a series of equivalent or similar features.

[0037] As Figures 3 - 5 shown, a pilot valve spool of the present invention that can be quickly opened, reduce thrust, and have low leakage includes a valve body 1. A balance hole is provided around the valve body 1, and a flow passage hole is provided inside the valve body 1;

[0038] It further includes a valve core 2, which is installed in the balance hole. The gap formed between the valve core 2 and the balance hole is the flow area. One end of the valve core 2 has a curved surface section 21, and the curved surface section 21 is buckled into the flow passage hole and the valve core 2 seals the flow passage hole.

[0039] It further includes a valve stem 3, which extends into the valve body 1 and is threadedly connected to the other end of the valve core 2.

[0040] A first cutting plane 23 is opened in the middle of the curved surface section 21 of the valve core 2, and a second cutting plane 24 is opened perpendicular to the first cutting plane 23 on both sides of the curved surface section 21. The flow area when the valve core 2 is opened is enlarged through the first cutting plane 23 and the cutting plane.

[0041] A sealing surface 22 is provided at the junction of the valve core 2 and the curved surface section 21. There is a sealing contact surface in the flow passage hole, and the valve core 2 seals the flow passage hole through the sealing surface 22.

[0042] Such as Figure 6 and Figure 7 shown, the pilot valve core 2 of the present utility model enlarges the flow area, but still retains the sealing surface 22. To ensure the strength of the valve core 2 after milling, some dimensions are defined and agreed upon here.

[0043] Among them, the bottom surface of the first cutting plane 23 is an arc-shaped bottom surface R2. The shortest straight-line distance from the center of the arc-shaped bottom surface R2 to the sealing surface 22 is Z, and Z satisfies Z≥R2 + 0.1. R2 satisfies R2≤(X - 10) / 2, where X is the maximum outer diameter of the curved surface section 21 of the valve core 2. One side end surface of the curved surface section 21 has a chamfer R1, and R1 satisfies R1 = X / 5. The curved surface section 21 forms an angle B with the horizontal plane, and the angle B is 15 degrees - 45 degrees. The thickness of the thinnest curved surface section 21 between the two second cutting planes 24 is W, and W≥10. An arc section R4 is formed at the bottom surface position of each second cutting plane 24, and the arc section R4 satisfies R4≈3W / 4. The straight-line length of the arc section is Y.

[0044] Figure 3 In Figure 1 combined with Figure 2 , P1 = P2, S1>S2, F1 = S1xP1>F2 = S2xP2. The actual thrust of this structure is F1 - F2<F1, achieving a reduction in thrust, enlarging A2, increasing the flow area, significantly shortening the balance time, and realizing quick opening.

[0045] The above are only specific embodiments of the present utility model, but the protection scope of the present utility model is not limited thereto. Any changes or substitutions that can be thought of without creative efforts shall be covered within the protection scope of the present utility model. Therefore, the protection scope of the present utility model shall be subject to the protection scope defined by the claims.

Claims

1. A pilot valve spool that can be quickly opened, reduce thrust, and have low leakage, characterized in that, Comprising: A valve body (1), around which a balance hole is provided in a circle on the valve body (1), and a flow passage hole is provided inside the valve body (1); A valve core (2), which is installed in the balance hole, and the gap formed between the valve core (2) and the balance hole is the flow area. One end of the valve core (2) has a curved surface section (21), and the curved surface section (21) is buckled into the flow passage hole and the valve core (2) seals the flow passage hole; A valve stem (3), which extends into the valve body (1) and is threadedly connected to the other end of the valve core (2); A first cut surface (23) is opened in the middle of the curved surface section (21) of the valve core (2), and a second cut surface (24) is opened perpendicular to the first cut surface (23) on both sides of the curved surface section (21). The flow area when the valve core (2) is opened is enlarged through the first cut surface (23) and the cut surface.

2. The pilot valve spool capable of quick opening, thrust reduction, and low leakage according to claim 1, characterized in that: A sealing surface (22) is provided at the junction of the valve core (2) and the curved surface section (21), and there is a sealing contact surface in the flow passage hole. The valve core (2) seals the flow passage hole through the sealing surface (22).

3. The pilot valve spool capable of quick opening, thrust reduction, and low leakage according to claim 1, wherein: The bottom surface of the first cut surface (23) is an arc bottom surface R2, and the shortest straight-line distance from the center of the arc bottom surface R2 to the sealing surface (22) is Z.

4. The pilot valve spool capable of quick opening, thrust reduction, and low leakage according to claim 3, characterized in that: The Z satisfies Z≥R2 + 0.

1.

5. The pilot valve spool capable of quick opening, thrust reduction, and low leakage according to claim 3, wherein: The R2 satisfies R2≤(X - 10) / 2, where X is the maximum outer circle diameter of the curved surface section (21) of the valve core (2).

6. The pilot valve spool capable of quick opening, thrust reduction, and low leakage according to claim 1, wherein: One side end surface of the curved surface section (21) has a chamfer R1, and the R1 satisfies R1 = X / 5.

7. The pilot valve spool capable of quick opening, thrust reduction, and low leakage according to claim 1, characterized in that: An angle B is formed between the curved surface section (21) and the horizontal plane, and the angle B is 15 degrees - 45 degrees.

8. The pilot valve spool capable of quick opening, thrust reduction, and low leakage according to claim 1, wherein: The thickness of the thinnest curved surface section (21) between the two second cut surfaces (24) is W, and the W≥10.

9. The pilot valve spool capable of quick opening, thrust reduction and low leakage according to claim 1, characterized in that: An arc section R4 is formed at the bottom surface position of each second cut surface (24), and the arc section R4 satisfies R4≈3W / 4, and the straight-line length of the arc section is Y.

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