Method for obtaining control valve spool curved surface and control valve throttling component

Abstract

The present invention provides a method for obtaining a control valve spool curved surface and a control valve throttling component, belonging to the field of regulating equipment. The method includes the following steps: according to the geometric structure of the control valve, obtain a model of the spool curved surface of the control valve with respect to the theoretical flow coefficient at a preset opening; according to the spatial relationship between the spool and the valve seat at the preset opening and the model, obtain the design coordinate data of the spool curved surface at the preset opening; adjust the preset opening, obtain the design coordinate data of the spool curved surface at each preset opening, and obtain the spool curved surface of the control valve according to the design coordinate data of the spool curved surface at each preset opening. The control valve throttling component includes a spool, and the throttling curved surface of the spool is obtained by using the method for obtaining the spool curved surface of the control valve described above. The present invention obtains the spool curved surface model by means of theoretical design and simulation correction. Compared with the traditional design method, it can improve the design efficiency, reduce the design error, and enable the control valve to obtain higher adjustment accuracy.

Description

Technical Field

[0001] The present invention relates to the field of regulating devices, and particularly to a method for obtaining a valve core surface of a regulating valve and a throttling assembly of a regulating valve. Background Art

[0002] The single-seat regulating valve is a key component for controlling the flow rate in an industrial system, and its mainstream regulating characteristics are of two types: linear and equal percentage. At present, when designing the valve core surface, it is generally designed according to the principle that the area ratio is equal to the flow coefficient ratio. However, in reality, the relationship between the two is not a simple and pure linear relationship, resulting in a large error. In addition, some designers will also perform simulation trial and error on the basis of the design where the area ratio is equal to the flow coefficient ratio, and rely on experience for re-analysis and design to improve the design accuracy. However, it often takes a lot of time, and the design accuracy is not satisfactory. Therefore, the main problems in the current design of the valve core of the regulating valve are that the regulating accuracy is too poor when designed by the proportional method, and the design takes too long when designed by the trial-and-error method. Summary of the Invention

[0003] In view of the above-mentioned deficiencies of the prior art, the purpose of the present invention is to provide a method for obtaining a valve core surface of a regulating valve and a throttling assembly of a regulating valve, which is used to solve the difficulties of large design errors and long design cycles of the valve core surface in the prior art, and the problem of poor regulating accuracy of the regulating valve.

[0004] To achieve the above purpose and other related purposes, the present invention provides a method for obtaining a valve core surface of a regulating valve, including the following steps:

[0005] According to the geometric structure of the regulating valve, obtain a model of the valve core surface of the regulating valve with respect to the theoretical flow coefficient at a preset opening degree;

[0006] According to the spatial relationship between the valve core and the valve seat at the preset opening degree and the model, obtain the design coordinate data of the valve core surface at the preset opening degree;

[0007] Adjust the preset opening degree, obtain the design coordinate data of the valve core surface at each preset opening degree, and obtain the valve core surface of the regulating valve according to the design coordinate data of the valve core at each preset opening degree.

[0008] Optionally, obtain the theoretical flow coefficient according to the preset opening degree,

[0009] The model of the valve core surface of the regulating valve with respect to the theoretical flow coefficient at the preset opening degree includes a correction coefficient,

[0010] Preset the correction coefficient, obtain the flow channel model of the regulating valve at the preset opening degree according to the preset correction coefficient and the preset opening degree, and perform simulation analysis to obtain the simulation flow coefficient;

[0011] Compare the simulated flow coefficient and the theoretical flow coefficient. If the error between the simulated flow coefficient and the theoretical flow coefficient is less than the preset error, the preset correction coefficient is the correction coefficient at the preset opening; otherwise, modify the preset correction coefficient and compare the simulated flow coefficient and the theoretical flow coefficient again until the error between the simulated flow coefficient and the theoretical flow coefficient is less than the preset error.

[0012] Optionally, fit the design coordinate data of the valve core surface at each preset opening to obtain the valve core surface.

[0013] Optionally, the model expression of the valve core surface with respect to the theoretical flow coefficient at the preset opening is:

[0014]

[0015] where i is the opening of the regulating valve, D c is the seat diameter, A1 is the total flow area at the inlet of the regulating valve, x i is the minimum distance between the minimum throttling point on the valve core surface and the valve core axis at the i-th opening of the regulating valve, y i is the minimum distance between the minimum throttling point on the valve core surface and the seat sealing surface at the i-th opening of the regulating valve, α i is the correction coefficient, C vi is the theoretical flow coefficient at the i-th opening of the regulating valve.

[0016] Optionally, the regulating characteristics of the regulating valve include linear type and equal percentage type.

[0017] Optionally, the flow characteristic expression of the linear type regulating valve is:

[0018] The flow characteristic expression of the equal percentage type regulating valve is:

[0019] C vmax is the theoretical rated flow coefficient of the regulating valve; R is the adjustable ratio of the regulating valve; L i is the stroke of the regulating valve at the i-th opening; L max is the rated stroke of the regulating valve, C vi is the theoretical flow coefficient at the i-th opening of the regulating valve.

[0020] Optionally, the design coordinate data of the valve core surface at the preset opening satisfies:

[0021]

[0022] where i is the opening of the regulating valve, D c is the seat diameter, L maxis the rated stroke of the regulating valve, θ is the angle between the generatrix of the conical side surface of the minimum throttling surface of the valve core and the valve seat sealing plane at the i-th opening of the regulating valve, and x i ′ is the designed abscissa of the valve core surface at the i-th opening of the regulating valve, which is equal to the minimum distance x between the minimum throttling point on the valve core surface and the valve core axis at the i-th opening of the regulating valve i , y i ′ is the designed ordinate of the valve core surface at the i-th opening of the regulating valve.

[0023] Optionally, the regulating characteristics of the regulating valve include a linear type and an equal percentage type. For the regulating valve of the linear type, the preset error ≤ 10%, and for the regulating valve of the equal percentage type, the preset error is ≤ 5%.

[0024] Optionally, taking the plane passing through the valve core axis as the reference plane, according to the design coordinate data of the valve core surface at each preset opening on the reference plane, a contour curve is fitted, and the swept trajectory of the contour curve rotating around the axis of the valve core is the valve core surface.

[0025] The present invention also provides a throttling assembly of a regulating valve, including a valve core, and the throttling surface of the valve core is obtained by using the method for obtaining the valve core surface of the regulating valve described in any one of the above.

[0026] As described above, the method for obtaining the valve core surface of a regulating valve and the throttling assembly of a regulating valve according to the present invention have the following beneficial effects: Since the valve core surface model is obtained by means of theoretical design and simulation correction, compared with the traditional design method, the design efficiency can be improved, the design error can be reduced, and the regulating valve can obtain higher regulating accuracy. Description of the Drawings

[0027] Figure 1 It shows a schematic diagram of the throttling model and the valve core surface design coordinate system of the regulating valve in the embodiment of the present invention;

[0028] Figure 2 It shows a partial schematic diagram of the minimum throttling point of the regulating valve in the embodiment of the present invention;

[0029] Figure 3 It shows a flowchart of the method for determining the correction coefficient in the embodiment of the present invention;

[0030] Figure 4 It shows the linear valve core surface in the embodiment of the present invention;

[0031] Figure 5 It shows the equal percentage valve core surface in the embodiment of the present invention;

[0032] Figure 6 It shows the vortex core pressure nephogram of the cross-section of the internal flow field of the valve corresponding to the linear valve core surface in the embodiment of the present invention;

[0033] Figure 7 It shows the streamline contour map of the cross-section of the internal flow field of the valve corresponding to the linear valve core surface in the embodiment of the present invention;

[0034] Figure 8 It shows the vortex core pressure contour map of the cross-section of the internal flow field of the valve corresponding to the equal percentage valve core surface in the embodiment of the present invention;

[0035] Figure 9 It shows the streamline contour map of the cross-section of the internal flow field of the valve corresponding to the equal percentage valve core surface in the embodiment of the present invention;

[0036] Figure 10 It shows the theoretical and simulated flow characteristic curves corresponding to the linear valve core surface in the embodiment of the present invention;

[0037] Figure 11 It shows the theoretical and simulated flow characteristic curves corresponding to the equal percentage valve core surface in the embodiment of the present invention.

[0038] Explanation of reference numerals: valve core 1, valve seat 2. Detailed implementation manners

[0039] The following uses specific specific examples to illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0040] It should be noted that the illustrations provided in this embodiment only schematically illustrate the basic concept of the present invention. Therefore, only the components related to the present invention are shown in the drawings, rather than being drawn according to the number, shape, and size of the components in actual implementation. The type, quantity, and ratio of each component in actual implementation can be arbitrarily changed, and the component layout type may also be more complex. The structures, ratios, sizes, etc. shown in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those skilled in this technology to understand and read, and are not used to limit the limiting conditions under which the present invention can be implemented. Therefore, they do not have technical substantive significance. Any modification of the structure, change of the proportional relationship, or adjustment of the size, without affecting the effects that the present invention can produce and the purposes that can be achieved, should still fall within the scope that can be covered by the technical content disclosed by the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle", and "one" used in this specification are only for the convenience of clear narration, rather than used to limit the scope within which the present invention can be implemented. The change or adjustment of their relative relationships, without substantial change in the technical content, should also be regarded as the scope within which the present invention can be implemented.

[0041] Such asFigure 1 As shown in the figure, the throttle component of the regulating valve includes a valve seat 2 and a valve core 1, and the valve core surface of the valve core 1 cooperates with the valve seat 2. The valve core 1 moves along its axis to control the opening degree of the regulating valve. This embodiment provides a method for obtaining the valve core surface of the regulating valve, including the following steps:

[0042] S1. According to the geometric structure of the regulating valve, obtain the model of the valve core surface of the regulating valve with respect to the theoretical flow coefficient at a preset opening degree;

[0043] S2. According to the spatial relationship between the valve core and the valve seat at the preset opening degree and the model, obtain the design coordinate data of the valve core surface at the preset opening degree;

[0044] S3. Adjust the preset opening degree, obtain the design coordinate data of the valve core surface at each preset opening degree, and obtain the valve core surface of the regulating valve according to the design coordinate data of the valve core surface at each preset opening degree.

[0045] Specifically, in step S1, the regulating characteristics of the regulating valve include a linear type and an equal percentage type.

[0046] Based on the fluid mechanics theory, the flow coefficient C of the regulating valve at the opening degree i can be obtained vi Expressed as:

[0047]

[0048] Where:

[0049]

[0050] ε i Is the flow resistance coefficient of the regulating valve at the opening degree i; d1 is the inlet diameter of the regulating valve, d i Is the equivalent diameter of the minimum throttling part of the regulating valve at the opening degree i, with the unit of cm; A1 is the inlet flow area of the regulating valve, A i Is the flow area of the minimum throttling part of the regulating valve at the opening degree i, with the unit of cm 2 .

[0051] Combining the above formulas, it can be obtained that:

[0052]

[0053] Considering factors such as energy loss and differences in valve shapes, a correction coefficient α is added to the above formula i , and it can be obtained that:

[0054]

[0055] The throttling model of the regulating valve is as Figure 1 And Figure 2As shown in the figure, based on its geometric structure, the flow area at the minimum throttling point when the regulating valve is at the i-th opening can be obtained:

[0056]

[0057] Among them, taking the plane passing through the axis of the valve core 1 as the reference plane, N and N1 are two points on the valve core at the minimum throttling point on the reference plane, and the distance between N and N1 is equal to d i ; M and M1 are two points on the valve seat sealing plane on the reference plane, and the distance between M and M1 is equal to the diameter D of the valve seat sealing plane c ; l i is the length of the generatrix of the conical side surface at point N on the minimum throttling surface between the valve core and the valve seat when the regulating valve is at the i-th opening, and l i is equal to the distance between point M and point N, that is, the distance between point M1 and point N1.

[0058] Taking the center point between M and M1 as the origin, the positive direction of the abscissa along the direction of point M1, and the positive direction of the ordinate along the valve core opening direction, a rectangular coordinate system for the valve core movement is established. The coordinates of point N1 are (x i , y i ), then there is:

[0059] d i = 2x i

[0060]

[0061] By combining the area formula of the minimum throttling point of the regulating valve obtained based on the fluid mechanics theory and the geometric model of the throttling element, the model expression of the valve core for the theoretical flow coefficient at the i-th opening is:

[0062]

[0063] Among them, i is the opening of the regulating valve, D c is the valve seat diameter, A1 is the total flow area at the inlet of the regulating valve, x i is the minimum distance between the minimum throttling point on the valve core surface and the valve core axis when the regulating valve is at the i-th opening, y i is the minimum distance between the minimum throttling point on the valve core surface and the valve seat sealing plane when the regulating valve is at the i-th opening, and α i is the correction coefficient. At the same time, according to the adjustable ratio R and the opening i of the regulating valve, the theoretical flow coefficient C vi of the regulating valve corresponding to the opening i can be obtained.

[0064] Specifically, the regulating characteristics of the regulating valve include linear type and equal percentage type.

[0065] For the linear type, the flow characteristic expression of the regulating valve is:

[0066]

[0067] For the equal percentage type, the flow characteristic of the control valve is expressed as:

[0068]

[0069] where C vmax is the theoretical rated flow coefficient of the control valve; R is the adjustable ratio of the control valve; L i is the stroke of the control valve at the i-th opening; L max is the rated stroke of the control valve, and C vi is the theoretical flow coefficient of the control valve at the i-th opening.

[0070] When the inlet area A1 of the control valve, the rated flow coefficient C vmax , the adjustable ratio R, the rated stroke L max , the seat diameter D c , and the correction coefficient α are all determined, the model expressions of the spool surface of the linear type and the equal percentage type with respect to the theoretical flow coefficient at the i-th opening can be obtained.

[0071] In step S2, a spool surface design coordinate system (x′, y′) as shown in Figure 1 is established. According to the spatial position relationship between the spool and the seat, the relationship formula of the design abscissa x i ′ and the design ordinate y i ′ of the spool surface of the control valve at the i-th opening is obtained:

[0072]

[0073] where i is the opening of the control valve; D c is the seat diameter; L max is the rated stroke of the control valve; the magnitude of x i ′ is equal to the minimum distance between the minimum throttling point on the spool surface of the control valve at the i-th opening and the spool axis, that is, equal to x i in the model expression of the spool surface with respect to the theoretical flow coefficient; θ is the angle between the generatrix of the conical side surface of the minimum throttling surface of the spool and the seat sealing plane at the i-th opening of the control valve.

[0074] According to the above method, each opening i of the control valve is preset, and the design coordinates (x i ′, y i′), then fit the design coordinate points of the valve core surface at each preset opening degree, obtain the projected contour line of the valve core surface on the reference plane, and then rotate the fitted contour line 360° along the axis of the valve core. The surface obtained by sweeping the contour line is the valve core surface of the regulating valve.

[0075] In this embodiment, in step S1, the model of the valve core surface of the regulating valve with respect to the theoretical flow coefficient at the preset opening degree i includes a correction coefficient α i , preset the correction coefficient, and according to the preset correction coefficient and the preset opening degree, obtain the flow channel model of the regulating valve at the preset opening degree and conduct a simulation analysis to obtain the simulated flow coefficient;

[0076] In addition, according to the preset opening degree i and the adjustable ratio R of the regulating valve, obtain the theoretical flow coefficient,

[0077] Compare the simulated flow coefficient and the theoretical flow coefficient. If the simulation C vi and the theoretical C vi The error between them is less than the preset error δ i , then the preset correction coefficient α i is the correction coefficient of the regulating valve at the corresponding opening degree i. If the simulation C vi and the theoretical C vi The error between them is greater than or equal to the preset error δ i , then modify the preset correction coefficient α i , and then re - conduct the simulation analysis, and compare the newly obtained simulation C vi and the theoretical C vi , until the error between the simulation C vi and the theoretical C vi is less than the preset error δ i .

[0078] Since the regulation characteristics of the regulating valve include linear type and equal percentage type, for the linear type regulating valve, the preset error δ i ≤ 10%, for the equal percentage type regulating valve, the preset error δ i ≤ 5%. The higher the accuracy requirement, the smaller the preset error. In this embodiment, for the linear type regulating valve, its preset error δ i is 5%, and for the equal percentage type regulating valve, its preset error δ i is 3%.

[0079] Adjust the opening degree i of the regulating valve, and repeat the above steps according to the opening degree i to obtain the correction coefficient α at each opening degree iIn this embodiment, for an equal percentage type control valve, the preset opening degrees i are respectively 10%, 20%, 30%... 100%. For a linear type control valve, the valve core curved surface can be designed as a linear curved surface between 20% and 80% of the opening degree. Therefore, the preset opening degrees i are respectively 10%, 20%, 80%, 100%.

[0080] The specific determination method of the correction coefficient is as Figure 3 shown. In addition, the determined linear valve core curved surface correction coefficient and equal percentage valve core curved surface correction coefficient are respectively applicable to other C vmax of the same caliber single-seat control valves of their own within a certain range for the design of the valve core curved surface, and both have relatively high design accuracy. It can greatly improve the design efficiency of the valve core curved surface, reduce its design error, and enable the control valve to obtain higher adjustment accuracy.

[0081] This embodiment also provides a throttle assembly for a control valve, including a valve core 1 and a valve seat 2. The throttle curved surface of the valve core in the throttle assembly of the control valve is obtained by using the method for obtaining the control valve core curved surface described in any one of the above items.

[0082] During actual implementation, taking a single-seat control valve with an adjustable ratio R = 50:1, a rated flow coefficient C vmax = 45, a rated stroke L max = 38 mm, a valve seat diameter of D c = 63 mm, and a nominal diameter DN80 as an example, through the above method, the obtained linear valve core curved surface and equal percentage valve core curved surface are respectively as Figure 4 and Figure 5 shown.

[0083] For the DN80-C vmax 45 single-seat control valve obtained above, a flow field simulation analysis is carried out. The length of the pipeline in front of the valve is taken as 2 times the nominal diameter of the pipeline, and the length of the pipeline behind the valve is taken as 6 times the nominal diameter of the pipeline; the medium is normal temperature water; the inlet is the total pressure, taken as 1500 kPa; the outlet is the static pressure, taken as 500 kPa; the standard k-ε turbulence model is adopted; the maximum residual values of the continuity equation, momentum equation, and turbulence equation are all less than 1×10 -4 ; the flow direction of the medium is low-in and high-out.

[0084] At 100% opening degree, the vortex core pressure contour map and streamline contour map of the internal flow field of the control valve corresponding to the linear valve core curved surface are respectively as Figure 6 and Figure 7 shown. The vortex core pressure contour map and streamline contour map of the internal flow field of the control valve corresponding to the equal percentage valve core curved surface are respectively as Figure 8 and Figure 9 shown. From Figures 6 to 9 it can be seen that for the DN80-C vmaxFor a 45 single-seat regulating valve, when the valve is fully opened, a large number of vortices are formed in the valve cavity of the linear and equal percentage valve core curves, and the maximum medium flow rate appears at the minimum throttling point where the valve core and valve seat cooperate.

[0085] Simulation C vi Calculated by the following formula:

[0086]

[0087] Where Q is the measured volume flow rate, obtained through simulation, in m 3 / h; Δp i is the pressure difference between the upstream and downstream pressure ports of the valve under the regulating valve opening i, obtained through simulation, and its unit is kPa; ρ1 is the density of the fluid, and its unit is kg / m 3 ; ρ0 is the density of water at 15.5℃, which is 999kg / m 3 ; N1 is the numeric constant 0.0865.

[0088] For DN80-C vmax 45 single-seat control valve, through simulation analysis and theoretical C vi Computation and Simulation C vi Calculate and obtain the theoretical C of the valve model corresponding to the linear valve core surface and the equal percentage valve core surface at 10%, 20%...100% opening respectively. vi and Simulation C vi The relative error between .

[0089] The details are shown in the following table:

[0090]

[0091] It can be seen from the above table that the DN80-C vmax For the 45 single-seat regulating valve, the relative error between the simulation and theoretical flow coefficient of the linear valve core curve at each opening is within 5%. The relative error between the simulation and theoretical flow coefficient of the equal percentage valve core curve at each opening is within 2%.

[0092] In addition, for DN80-C vmax 45 single-seat regulating valve, using the data in the table above, draw the theoretical and simulated flow characteristic curves of the linear valve core surface and the equal percentage valve core surface corresponding to the valve model, such as Figure 10 and Figure 11 As shown in the figure, it can be seen that the valve simulation flow characteristic curves and theoretical flow characteristic curves corresponding to the two types of valve core surfaces are highly consistent, which proves that the method for determining the valve core surface is effective and feasible.

[0093] In summary, in the method for obtaining the valve core surface of the regulating valve and the throttling component of the regulating valve according to the present invention, the model of the valve core opening degree with respect to the theoretical flow coefficient includes a correction coefficient, and the correction coefficient is obtained through simulation optimization, which can correct the valve core surface. Compared with the traditional linear type and equal percentage type valve core surface design methods, higher design accuracy can be obtained, the regulating performance of the valve can be improved, and support can be provided for the accurate selection of single-seat regulating valves. In addition, the determined linear valve core surface correction coefficient and equal percentage valve core surface correction coefficient are respectively applicable to other C of single-seat regulating valves of the same caliber within a certain range vmax in the design of the valve core surface, and both have high design accuracy, which can greatly improve the design efficiency of the valve core surface.

[0094] The above embodiments are only illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes completed by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A method for obtaining the curved surface of a regulating valve spool, characterized in that, It includes the following steps: According to the geometric structure of the regulating valve, obtain the model of the spool surface of the regulating valve with respect to the theoretical flow coefficient at a preset opening degree; According to the spatial relationship between the spool and the valve seat at the preset opening degree and the said model, obtain the design coordinate data of the spool surface at the preset opening degree; Adjust the preset opening degree, obtain the design coordinate data of the spool surface at each preset opening degree, and obtain the spool surface of the regulating valve according to the design coordinate data of the spool surface at each preset opening degree; According to the said preset opening degree, obtain the theoretical flow coefficient, The model of the spool surface of the regulating valve with respect to the theoretical flow coefficient at the preset opening degree includes a correction coefficient, Preset the correction coefficient, according to the preset correction coefficient and the preset opening degree, obtain the flow channel model of the regulating valve at the preset opening degree and conduct a simulation analysis to obtain the simulated flow coefficient; Compare the simulated flow coefficient with the theoretical flow coefficient. If the error between the simulated flow coefficient and the theoretical flow coefficient is less than the preset error, then the preset correction coefficient is the correction coefficient at the preset opening degree. Otherwise, modify the preset correction coefficient and re-compare the simulated flow coefficient with the theoretical flow coefficient until the error between the simulated flow coefficient and the theoretical flow coefficient is less than the preset error; The model expression of the spool surface with respect to the theoretical flow coefficient at the preset opening degree is: where, i is the opening degree of the control valve, D c is the seat diameter, A1 is the total flow area at the inlet of the control valve, x i is the minimum distance between the minimum throttling point on the spool surface and the spool axis at the i opening degree of the control valve, y i is the minimum distance between the minimum throttling point on the spool surface and the seat sealing plane at the i opening degree of the control valve, α i is the correction coefficient, C vi is the theoretical flow coefficient at the i opening degree of the control valve.

2. The method for obtaining the curved surface of a regulating valve spool according to claim 1, characterized in that: Fit the design coordinate data of the spool surface at each preset opening degree to obtain the spool surface.

3. A method for obtaining the curved surface of a regulating valve spool according to claim 1, characterized in that: The regulating characteristics of the said regulating valve include linear type and equal percentage type.

4. The method for obtaining the spool surface of a regulating valve according to claim 3, wherein: The flow characteristic of the regulating valve of the linear type is expressed as: The flow characteristics of an equal percentage type control valve are expressed as: C vmax is the theoretical rated flow coefficient of the control valve; R is the adjustable ratio of the control valve; L i is the stroke of the control valve at the i-th opening; L max is the rated stroke of the control valve, C vi is the theoretical flow coefficient of the control valve at the i-th opening.

5. A method for obtaining the curved surface of a regulating valve spool according to claim 1, characterized in that: The design coordinate data of the valve core surface at the preset opening satisfy: where i is the opening degree of the regulating valve, D c is the seat diameter, L max is the rated stroke of the regulating valve, θ is the angle between the generatrix of the conical side surface of the minimum throttling surface at the i opening degree of the regulating valve and the valve seat sealing plane, x i ′ is the designed abscissa of the valve core surface at the i opening degree of the regulating valve, equal to the minimum distance x i between the minimum throttling point on the valve core surface and the valve core axis at the i opening degree of the regulating valve, y i ′ is the designed ordinate of the valve core surface at the i opening degree of the regulating valve.

6. The method for obtaining the curved surface of a regulating valve spool according to claim 1, wherein: The regulating characteristics of the said regulating valve include linear type and equal percentage type. For a regulating valve of linear type, the preset error ≤ 10%, and for a regulating valve of equal percentage type, the preset error ≤ 5%.

7. A method for obtaining the curved surface of a regulating valve spool according to claim 2, characterized in that: Taking the plane passing through the spool axis as the reference plane, according to the design coordinate data of the spool surface at each preset opening degree on the reference plane, fit to obtain a contour curve, and the swept trajectory of the contour curve rotating around the axis of the spool is the spool surface.

8. A throttle assembly for a control valve, characterized in that: It includes a spool, and the throttling surface of the spool is obtained by using the method for obtaining the spool surface of a regulating valve according to any one of claims 1 to 7.

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