Angle stroke test plate for regulating valve and its calculation method

Abstract

The application relates to a kind of angular stroke test plate for regulating valve and its calculation method, including arc body, the straight line segment center of arc body is provided with right triangle notch, including the following steps: the concentric fixation of arc body is on the rotating shaft of regulating valve and the rotation of arc body 90 degrees, further draw ellipse curve;According to the size of arc length L to calculate the angle beta;Further get a monomial cubic equation: Ax 3 +Bx 2 +Cx+D=0;Adopting the formula method of gold to solve the above monomial cubic equation;The application can accurately simulate the angular stroke trajectory of regulating valve when rotating by means of arc body, and can accurately calculate the value of rotation angle beta according to arc length L, and can accurately grasp the change process of rotation angle beta, thereby greatly facilitating the performance improvement of regulating valve.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of angle stroke test plate of regulating valve and its calculation method. BACKGROUND

[0002] Regulating valve is in the field of industrial automation process control, by receiving the control signal of regulating control unit output, change medium flow, pressure, temperature, liquid level etc. Process parameters are changed by power operation, and it is the final control element in industrial production process control, and it is essential;If the performance of regulating valve is to be improved, the angle stroke of regulating valve must be measured to facilitate the improvement of structure.

[0003] In prior art, there is no effective calculation method to improve the accuracy of regulating valve angle stroke measurement, which leads to the performance of regulating valve cannot be effectively improved, and it is urgent to be solved. SUMMARY

[0004] In view of the above status of prior art, the technical problem to be solved by the present application is to provide a kind of angle stroke test plate for regulating valve and its calculation method, which can accurately simulate the angle stroke trajectory of regulating valve when rotating and accurately calculate the value of rotation angle β according to arc length L to accurately grasp the change process of rotation angle β, thereby greatly improving the performance of regulating valve.

[0005] The technical scheme adopted by the present application to solve the above technical problems is: a kind of angle stroke test plate for regulating valve, characterized by comprising arc body, and straight line segment center of the arc body is provided with right triangle notch.

[0006] A kind of angle stroke calculation method for regulating valve, characterized by comprising the following steps:

[0007] S1: the arc body is concentrically fixed on the rotating shaft of regulating valve and is rotated 90 degrees, and then an elliptical curve is drawn;

[0008] When D>d, the long semi-axis of the elliptical curve is a, and the short semi-axis is b, and the circumference is 2πa+4 (a-b);

[0009] According to symmetry, the circumference at the quarter of the ellipse (rotation angle β is π / 2) is πa / 2+a-b;

[0010] The relationship between the radius R of the ellipse and the rotation angle β is:

[0011] Wherein The eccentricity of the ellipse.

[0012] The relationship between the arc length L and the rotation angle β is:

[0013]

[0014] S2: Calculate the size of angle β according to the arc length L;

[0015] Note that angle β varies from 0 to π / 2, R(β) varies from b to a and monotonically increases, but the relationship is nonlinear;

[0016] Let:

[0017] R(β) = Aβ 2 +Bβ+C

[0018] Then

[0019]

[0020] From R(0) = b, The solution is:

[0021]

[0022]

[0023] C = b

[0024] The approximate analytical expression between the arc length L and the rotation angle β is obtained:

[0025] β is between [0, π / 2].

[0026] Further, a cubic equation is obtained: Ax 3 +Bx 2 +Cx+D = 0;

[0027] S3: Use the Shengjin formula method to solve the cubic equation: Ax 3 +Bx 2 +Cx+D = 0;

[0028] Where:

[0029]

[0030] The discriminant of the multiple root is:

[0031]

[0032] The total discriminant is:

[0033] Δ = Q 2 -4PR

[0034] According to the Shengjin discriminant method, we have:

[0035] (1) When a = b, a > 0, we have

[0036] (2) When a > b, delta < 0, the equation has three unequal real roots:

[0037]

[0038] Wherein:

[0039]

[0040] For this problem, the solution x1 < 0, the solution The solution x3 is in the interval [0, pi / 2]. The solution is:

[0041]

[0042] (3) When a < b, delta > 0, the equation has only one real root:

[0043]

[0044] Wherein:

[0045]

[0046] The relative error of calculation is related to the eccentricity of the ellipse, and the smaller the eccentricity is, the higher the precision is.

[0047] Compared with the prior art, the advantages of the present application are that: the present application can accurately simulate the angular travel trajectory of the regulating valve when rotating by means of the arc-shaped body, and can accurately calculate the value of the rotation angle beta according to the arc length L, and can accurately master the change process of the rotation angle beta, thereby greatly facilitating the improvement of the performance of the regulating valve. BRIEF DESCRIPTION OF DRAWINGS

[0048] Figure 1 The structure diagram of the arc-shaped body of the present application is shown in the figure;

[0049] Figure 2 The parameter distribution diagram of the present application is shown in the figure;

[0050] Figure 3 The travel diagram when the rotation angle beta of the present application is 90 degrees is shown in the figure. DETAILED DESCRIPTION

[0051] Unless otherwise defined, technical terms or scientific terms used in the present application shall have the same meaning as those commonly understood by a person of ordinary skill in the art to which the present application belongs. The terms "first", "second", and similar terms are used herein merely to distinguish one element from another, and are not intended to imply any order or sequence, unless otherwise defined. The terms "include", "comprise", and similar terms are intended to be inclusive, and not to exclude other elements or items. The terms "connected", "coupled", and similar terms are not limited to direct connections or physical connections, but can include indirect connections or indirect physical connections, such as electrical connections, whether direct or indirect, between two or more elements. The terms "upper", "lower", "left", "right", and similar terms are used merely to indicate relative positions, and can be changed when the absolute positions of the described objects are changed.

[0052] In order to keep the following description of the embodiments of the present application clear and concise, detailed descriptions of known functions and known components are omitted.

[0053] As shown in Figure 1 FIG. 1, an angular stroke test plate for a regulating valve includes an arcuate body 1 having a right-angled triangular notch 11 at the center of a straight line segment of the arcuate body 1.

[0054] As shown in Figures 2-3 FIG. 2, an angular stroke calculation method for a regulating valve includes the following steps:

[0055] S1: concentrically fix the arcuate body 1 on the rotating shaft of the regulating valve and rotate the arcuate body 1 by 90 degrees (i.e., the rotation angle β changes from 0 to π / 2), and then draw an elliptical curve 12; when D > d, the major axis of the elliptical curve 12 is a, the minor axis is b, and the circumference is 2πa + 4(a-b);

[0056] According to symmetry, the circumference at the quarter of the ellipse (the rotation angle β is π / 2) is πa / 2 + a-b;

[0057] The relationship between the elliptical radius R and the rotation angle β is:

[0058] where e is the eccentricity of the ellipse. The relationship between the arc length L and the rotation angle β is:

[0059]

[0060] This is an elliptical integral, and there is no analytical expression.

[0061] S2: calculate the size of the angle β according to the arc length L;

[0062]

[0063] ​Note that the angle β varies from 0 to π / 2, R(β) varies from b to a and monotonically increases, but the relationship is nonlinear;

[0064] Let:

[0065] R(β) = Aβ 2 +Bβ+C

[0066] Then

[0067]

[0068] From R(0) = b, Solve:

[0069]

[0070]

[0071] C = b

[0072] The approximate analytical expression between the arc length L and the rotation angle β is obtained:

[0073] β is between [0, π / 2].

[0074] Further, a cubic equation is obtained: Ax 3 +Bx 2 +Cx+D = 0

[0075] S3: Solve the cubic equation Ax 3 +Bx 2 +Cx+D = 0 using the Shengjin formula method

[0076] Where:

[0077]

[0078] The discriminant of multiple roots is:

[0079]

[0080] The total discriminant is:

[0081] Δ = Q 2 -4PR

[0082] According to the Shengjin discriminant method, we have:

[0083] 1. When a = b, a > 0, we have

[0084] 2. When a > b, Δ < 0, the equation has three unequal real roots:

[0085]

[0086] Wherein:

[0087]

[0088] For this problem, the solution x1 < 0, the solution The solution x3 is in the interval [0, pi / 2]. The solution is:

[0089]

[0090] 3. When a < b, delta > 0, the equation has only one real root:

[0091]

[0092] Wherein:

[0093]

[0094] The relative error of calculation is related to the eccentricity of the ellipse, and the smaller the eccentricity is, the higher the precision is.

[0095] The present application can accurately simulate the angular stroke trajectory of the regulating valve when rotating by means of the arc-shaped body 1, and can accurately calculate the value of the rotation angle beta according to the arc length L, and can accurately master the change process of the rotation angle beta, thereby greatly facilitating the improvement of the performance of the regulating valve.

[0096] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for calculating the angular stroke of a regulating valve, applied to the angular stroke test plate of a regulating valve, characterized by, The angle stroke test plate comprises an arcuate body, and a right triangle notch is arranged at the center of a straight line segment of the arcuate body; The angle stroke calculation method for the regulating valve comprises the following steps: S1: fixing the arcuate body concentrically on the rotating shaft of the regulating valve and rotating the arcuate body by 90 degrees, and then drawing an elliptical curve; When D>d, the major axis of the elliptical curve is a, the minor axis is b, and the circumference is 2πa+4(a-b); According to symmetry, the circumference at the quarter of the ellipse is πa / 2+a-b, and the rotation angle β is π / 2; The relationship between the radius R of the ellipse and the rotation angle β is: ； The relationship between the arc length L and the rotation angle β is: ； S2: calculating the size of the angle β according to the arc length L; It is noted that the angle β changes from 0 to π / 2, R(β) changes from b to a, and monotonically increases, but the relationship is nonlinear; Let: ； Then ； Solving gives: ； ； ； The approximate analytical expression relationship between the arc length L and the rotation angle β is obtained as follows: β is between [0, π / 2] ; Further, a monic cubic equation is obtained: ; S3: The monomial cubic equation is solved by using the Newton-Raphson formula method: ; Wherein: ； The multiple root discriminant is: ； The total discriminant is: ； According to the Shengjin discriminant method, there is: (1) when a = b, a > 0, there is ; (2) when a > b, <0, the equation has three distinct real roots: ； Wherein: ； For this problem, the solution solution , the solution In the interval [0, π / 2]; the solution is: ； (3) when a < b, > 0, the equation has only one real root: ； Wherein: ； The relative error of the calculation is related to the eccentricity of the ellipse, and the smaller the eccentricity is, the higher the precision is.

Images