Method for designing eccentric parameters of three-eccentric center butterfly valve

Abstract

The invention discloses a three-eccentric center butterfly valve eccentric parameter design method which comprises the following steps: establishing a rectangular coordinate system Y0Z according to a cone cutting valve plate, deflecting a cone by taking a 0 point as a center, and calculating a deflection angle; and radial offset of the cone and calculation of radial eccentricity and axial eccentricity. The method is rigorous, visual and clear in coordinate system establishment and parameter design calculation process logic, can be directly applied to structural design in the actual design process, and provides guidance for design of the three-eccentric center butterfly valve.

Description

Technical Field

[0001] The invention relates to the technical field of valve parameter design, and more particularly to an eccentric parameter design method for a triple-eccentric butterfly valve. Background Art

[0002] A butterfly valve is a valve that is opened and closed by rotating a disc-shaped valve plate (disc) around a valve stem. It mainly serves as a cutoff and throttling function in pipelines and is widely used in engineering. After many improvements, the traditional butterfly valve has been developed into single eccentric (axial eccentric), double eccentric (axial eccentric, radial eccentric), and triple eccentric (axial eccentric, radial eccentric, angular eccentric) butterfly valves. The sealing surface of the valve plate of the triple eccentric butterfly valve gradually disengages and gradually presses against the sealing surface of the valve seat, thereby reducing friction during the entire process of opening and closing.

[0003] The three eccentric parameters in the triple-eccentric butterfly valve are key design parameters in the manufacture of butterfly valves. Among them, the first eccentricity is the axial eccentricity of the rotating shaft relative to the sealing ring, the second eccentricity is the radial eccentricity of the rotating shaft relative to the center of the flow channel, and the third eccentricity is the angular eccentricity of the sealing cone surface relative to the center of the flow channel. The sealing pair of the triple-eccentric structure can make the sealing ring of the butterfly valve contactless with the valve seat during the switching process, eliminating the friction and wear of the sealing pair of the single-eccentric or double-eccentric butterfly valve during switching, and effectively extending the service life of the low-temperature butterfly valve.

[0004] There are few literatures on the design and calculation of the parameters of three-eccentric butterfly valves. After consulting the paper "Torque Calculation and Structural Optimization of Three-Eccentric Butterfly Valve", there are three parameter calculation methods, but the design and calculation steps in this paper are relatively complicated, with many formulas, and the variables are crossed during the solution process, which is not conducive to the calculation and design of the parameters.

[0005] Therefore, how to provide a simple and clear eccentric parameter design method for a three-eccentric butterfly valve that can be directly applied to structural design in the actual design process and provide design guidance for the design of a three-eccentric butterfly valve is an issue that technical personnel in this field urgently need to solve. Summary of the invention

[0006] In view of this, the present invention provides a simple and clear method for designing eccentric parameters of a triple eccentric butterfly valve, which can be directly applied to structural design in an actual design process and provides design guidance for the design of the triple eccentric butterfly valve.

[0007] In order to achieve the above object, the present invention adopts the following technical solution:

[0008] A method for designing eccentricity parameters of a triple-eccentric butterfly valve includes the following design steps:

[0009] Step 1, design the valve plate cone deflection angle Ψ:

[0010] The valve plate is obtained by cutting the plate body with a right cone and a rectangular coordinate system is established: the small diameter end face of the valve plate is the Y axis, the flow channel axial direction of the valve plate is the X axis, and the center point of the small diameter end face of the valve plate is the O point, and a rectangular coordinate system YOX is established;

[0011] Determine the straight line equations for the upper and lower sealing lines on the valve plate:

[0012] The linear equation of the straight line PP' is: Y = tan(θ)X + R;

[0013] The linear equation of the straight line QQ' is: Y = -tan(θ)XR;

[0014] Wherein, R is the length of the radius OP of the small diameter end of the valve plate, and θ is the semi-cone angle of the cone;

[0015] In order to reduce the wear of the valve plate sealing surface when opening and closing, the cone is deflected with point O as the center, and the deflection angle is Ψ.

[0016] Then the linear equations of BF and GH on the sealing surface of the valve plate after deflection are:

[0017] Straight Line BF:

[0018] Y=tan(θ-Ψ)X+Rcos(Ψ)-Rsin(Ψ)tan(θ-Ψ) (Formula 1) Straight line HG:

[0019] Y=-tan(θ+Ψ)X-Rcos(Ψ)-Rsin(Ψ)tan(θ+Ψ) (Formula 2)

[0020] Draw a straight line through B perpendicular to the valve plate sealing surface and intersecting the X axis at point B'. The intersection of BH and the X axis is O1. If the valve plate does not interfere, the valve plate rotation center distance c≥|OB'| is required. Similarly, draw a straight line through G perpendicular to the valve plate sealing surface and intersecting the X axis at point G'. If the valve plate does not interfere, the valve plate rotation center distance c≤|OG'| is required.

[0021] in:

[0022] |OB'|=|O1B|tan(θ-Ψ)+E={tan(θ-Ψ)E+Rcos(Ψ)-Rsin(Ψ)tan(θ-Ψ)}tan(θ-Ψ)+E (Formula 3) |OG'|=|OG|tan(θ+Ψ)={Rcos(Ψ)+Rsin(Ψ)tan(θ+Ψ)}tan(θ+Ψ) (Formula 4) The conditions for the valve plate to open without interference are:

[0023] |OB'|≤|OG'| (Formula 5)

[0024] Where R, θ, and valve plate thickness h are known values, Ψ is less than or equal to θ, and the value range of the deflection angle Ψ can be determined by combining (Formula 3), (Formula 4), and (Formula 5);

[0025] Step 2, design the valve radial eccentricity e+e':

[0026] Due to the eccentric angle, the cutting envelope of the valve plate is offset. In order to reduce the influence of the cutting envelope offset on the valve plate cutting, the positive cone angle after the deflection angle Ψ is offset along the radial direction. The offset is e+e', where e is the distance from the intersection of the cone generatrix and the valve plate minor diameter end face to the rotation center after the offset, and e' is the radial distance between the rotation center and the central axis of the valve flow channel.

[0027] P, P', Q, Q' are the intersection points of the right cone angle and the valve plate sealing surface when the cone angle is not deflected. C, C', D, D' are the intersection points of the cone angle and the valve plate sealing surface after rotation. From step 1, we know the equations of straight line PP', straight line QQ', straight line CC', and straight line DD'. If the thickness of the valve plate is E, then:

[0028] When the cone angle does not deflect:

[0029]

[0030] When the cone angle is deflected:

[0031] |OC|=Rcos(Ψ)-Rsin(Ψ)tan(θ-Ψ) (Formula 7)

[0032] |OC'|=tan(θ-Ψ)h+Rcos(Ψ)-Rsin(Ψ)tan(θ-Ψ) (Formula 8)

[0033] |OD|=Rcos(Ψ)+Rsin(Ψ)tan(θ+Ψ) (Formula 9)

[0034] |OD'|=tan(θ+Ψ)h+Rcos(Ψ)+Rsin(Ψ)tan(θ+Ψ) (Formula 10)

[0035] Then the radial eccentricity should be:

[0036] |OD'|-|OQ'|≤e+e'≤|OP'|-|OC'| (Formula 11)

[0037] In the formula, R, θ, and Ψ are known values. The range of radial eccentricity e+e' can be known from formula (11);

[0038] Step 3: Design the valve axial eccentricity

[0039] Line GG' is perpendicular to line A'G, and line GG' intersects the axis of the rotation center with point G'. Line BB' is perpendicular to line A'B, and line BB' intersects the axis of the rotation center with point B'. The eccentricity of the rotation center to the X-axis is e'. From step 1, we know that c should meet the following conditions:

[0040] |O'B'|≤c≤|O'G'| (Formula 12)

[0041] After the right cone is deflected by an angle and radially eccentric,

[0042]

[0043] From (Formula 3) and (Formula 4), we know that:

[0044] |O'B'|={tan(θ-Ψ)h+Rcos(Ψ)-Rsin(Ψ)tan(θ-Ψ)-e'}tan(θ-Ψ)+h (Formula 13)

[0045] |O'G'|={Rcos(Ψ)+Rsin(Ψ)tan(θ+Ψ)+e'}tan(θ+Ψ) (Formula 14)

[0046] Where R, θ, Ψ, and e' are all known values. Combining (Formula 12), (Formula 13), and (Formula 14), we can get the range of c, that is, the eccentricity of the rotary axis is

[0047] That is, according to the following formula, the three eccentricity parameters of the butterfly valve can be obtained: angular eccentricity Ψ, radial eccentricity e+e', and axial eccentricity

[0048] It can be seen from the above technical solution that, compared with the prior art, the present invention discloses a method for designing eccentric parameters of a three-eccentric butterfly valve. The method is established from a coordinate system, and the parameter design and calculation process is logically rigorous, intuitive and clear. It can be directly applied to structural design in the actual design process, providing guidance for the design of three-eccentric butterfly valves. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0050] Figure 1 Schematic diagram of a valve plate obtained by cutting a plate body with a right cone provided by the present invention.

[0051] Figure 2 It is a schematic diagram of the cone-cut valve plate after the positive cone deflection Ψ.

[0052] Figure 3 In Figure 3 -a is a schematic diagram of the right cone angle, Figure 3 -b is a schematic diagram of radial eccentricity.

[0053] Figure 4 Schematic diagram of three eccentricity parameters. DETAILED DESCRIPTION

[0054] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0055] The embodiment of the present invention discloses a method for designing eccentricity parameters of a triple-eccentric butterfly valve, comprising the following design steps:

[0056] Step 1, design the valve plate cone deflection angle Ψ:

[0057] The valve plate 2 is obtained by cutting the plate body with a right circular cone 1 and a rectangular coordinate system is established: the small diameter end face of the valve plate 2 is taken as the Y axis, the flow channel axial direction of the valve plate 2 is taken as the X axis, and the center point of the small diameter end face of the valve plate 2 is taken as the O point, and a rectangular coordinate system YOX is established;

[0058] Determine the linear equations of the upper and lower sealing lines of valve plate 2:

[0059] The linear equation of the straight line PP' is: Y = tan(θ)X + R;

[0060] The linear equation of the straight line QQ' is: Y = -tan(θ)XR;

[0061] Wherein, R is the length of the radius OP of the small diameter end of the valve plate, and θ is the semi-cone angle of the cone;

[0062] In order to reduce the wear of the valve plate sealing surface when opening and closing, the cone is deflected with point O as the center, and the deflection angle is Ψ.

[0063] Then the linear equations of BF and GH on the sealing surface of the valve plate after deflection are:

[0064] Straight Line BF:

[0065] Y=tan(θ-Ψ)X+Rcos(Ψ)-Rsin(Ψ)tan(θ-Ψ) (Formula 1) Straight line HG:

[0066] Y=-tan(θ+Ψ)X-Rcos(Ψ)-Rsin(Ψ)tan(θ+Ψ) (Formula 2)

[0067] Draw a straight line through B perpendicular to the valve plate sealing surface and intersecting the X axis at point B'. The intersection of BH and the X axis is O1. If the valve plate does not interfere, the valve plate rotation center distance c≥|OB'| is required. Similarly, draw a straight line through G perpendicular to the valve plate sealing surface and intersecting the X axis at point G'. If the valve plate does not interfere, the valve plate rotation center distance c≤|OG'| is required.

[0068] in:

[0069] |OB'|=|O1B|tan(θ-Ψ)+E={tan(θ-Ψ)E+Rcos(Ψ)-Rsin(Ψ)tan(θ-Ψ)}tan(θ-Ψ)+E (Formula 3)

[0070] |OG'|=|OG|tan(θ+Ψ)={Rcos(Ψ)+Rsin(Ψ)tan(θ+Ψ)}tan(θ+Ψ) (Formula 4)

[0071] The conditions for the valve plate to open without interference are:

[0072] |OB'|≤|OG'| (Formula 5)

[0073] Where R, θ, and valve plate thickness E are known values. By combining (Formula 3), (Formula 4), and (Formula 5), ​​we can determine {tan(θ-Ψ)E+Rcos(Ψ)-Rsin(Ψ)tan(θ-Ψ)}tan(θ-Ψ)+E≤{Rcos(Ψ)+Rsin(Ψ)tan(θ+Ψ)}tan(θ+Ψ). This formula can also be used to determine the range of the deflection angle Ψ.

[0074] Step 2, design the valve radial eccentricity e+e':

[0075] Due to the eccentric angle, the cutting envelope of the valve plate is offset. In order to reduce the influence of the cutting envelope offset on the valve plate cutting, the positive cone angle after the deflection angle Ψ is offset along the radial direction. The offset is e+e', where e is the distance from the intersection of the cone generatrix and the valve plate minor diameter end face to the rotation center after the offset, and e' is the radial distance between the rotation center and the central axis of the valve flow channel.

[0076] P, C, Q, D are the intersection points of the right cone angle and the valve plate sealing surface when the cone angle is not deflected. P', C', Q', D' are the intersection points of the cone angle and the valve plate sealing surface after rotation. From step 1, we know the equations of straight line PP', straight line QQ', straight line CC', and straight line DD'. If the thickness of the valve plate is E, then:

[0077] When the cone angle does not deflect:

[0078]

[0079] When the cone angle is deflected:

[0080] |OC|=Rcos(Ψ)-Rsin(Ψ)tan(θ-Ψ) (Formula 7)

[0081] |OC'|=tan(θ-Ψ)E+Rcos(Ψ)-Rsin(Ψ)tan(θ-Ψ) (Formula 8)

[0082] |OD|=Rcos(Ψ)+Rsin(Ψ)tan(θ+Ψ) (Formula 9)

[0083] |OD'|=tan(θ+Ψ)E+Rcos(Ψ)+Rsin(Ψ)tan(θ+Ψ) (Formula 10)

[0084] Then the radial eccentricity should be:

[0085] |OD'|-|OQ'|≤e+e'≤|OP'|-|OC'| (Formula 11)

[0086] In the formula, R, θ, and Ψ are known values, which can be obtained from formula (11):

[0087]

[0088] This formula can also give the range of radial eccentricity e+e';

[0089] Step 3: Design the valve axial eccentricity

[0090] Line GG' is perpendicular to line A'G, and line GG' intersects the axis of the rotation center with point G'. Line BB' is perpendicular to line A'B, and line BB' intersects the axis of the rotation center with point B'. The eccentricity of the rotation center to the X-axis is e'. From step 1, we know that c should meet the following conditions:

[0091] |O'B'|≤c≤|O'G'|(Formula 12)

[0092] After the right cone is deflected by an angle and radially eccentric,

[0093]

[0094] From (Formula 3) and (Formula 4), we know that:

[0095] |O'B'|={tan(θ-Ψ)E+Rcos(Ψ)-Rsin(Ψ)tan(θ-Ψ)-e'}tan(θ-Ψ)+E (Formula 13)

[0096] |O'G'|={Rcos(Ψ)+Rsin(Ψ)tan(θ+Ψ)+e'}tan(θ+Ψ) (Formula 14) Where R, θ, Ψ, and e' are all known values. Combining (Formula 12), (Formula 13), and (Formula 14), we can get

[0097] From this formula, we can know the value range of c, that is, the eccentricity of the rotary axis is

[0098] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0099] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for designing eccentricity parameters of a triple eccentric butterfly valve, characterized in that: The design steps include: Step 1: Design and determine the valve plate cone angle deflection angle Ψ: The valve plate (2) is obtained by cutting the plate body with a right circular cone (1) and a rectangular coordinate system is established: the small diameter end surface of the valve plate (2) is taken as the Y axis, the flow channel axial direction of the valve plate (2) is taken as the X axis, and the center point of the small diameter end surface of the valve plate (2) is taken as the point O, and a rectangular coordinate system YOX is established; Determine the straight line equations of the upper and lower sealing lines of the valve plate (2): The linear equation of the straight line PP' is: Y = tan(θ)X + R; The linear equation of the straight line QQ' is: Y = -tan(θ)XR; Wherein, R is the length of the radius OP of the small diameter end of the valve plate (2), and θ is the semi-cone angle of the cone; In order to reduce the wear of the valve plate sealing surface when opening and closing, the cone is deflected with point O as the center, and the deflection angle is Ψ. Then the linear equations of BF and GH on the sealing surface of the valve plate after deflection are: Straight Line BF: Y=tan(θ-Ψ)X+Rcos(Ψ)-Rsin(Ψ)tan(θ-Ψ) (Formula 1) Straight Line HG: Y=-tan(θ+Ψ)X-Rcos(Ψ)-Rsin(Ψ)tan(θ+Ψ) (Formula 2) Draw a straight line perpendicular to the valve plate sealing surface BF through B and intersect the X axis at point B'. The intersection of BH and the X axis is O1. If the valve plate does not interfere, the valve plate rotation center distance E is required, that is, C ≥ |OB'|. Similarly, draw a diameter perpendicular to the valve plate sealing surface GH through G and intersect the X axis at point G'. If the valve plate does not interfere, the valve plate rotation center distance c ≤ |OG'| is required; in: |OB'|=|O1B|tan(θ-Ψ)+E={tan(θ-Ψ)E+Rcos(Ψ)-Rsin(Ψ)tan(θ-Ψ)}tan(θ-Ψ)+E (Formula 3) |OG'|=|OG|tan(θ+Ψ)={Rcos(Ψ)+Rsin(Ψ)tan(θ+Ψ)}tan(θ+Ψ) (Formula 4) The conditions for the valve plate to open without interference are: |OB'|≤|OG'| (Formula 5) Where R, θ, and valve plate thickness h are known values, Ψ is less than or equal to θ, and the value range of the deflection angle Ψ can be determined by combining (Formula 3), (Formula 4), and (Formula 5); Step 2: Design and determine the valve radial eccentricity e+e': Due to the eccentric angle, the cutting envelope of the valve plate is offset. In order to reduce the influence of the cutting envelope offset on the valve plate cutting, the positive cone angle after the deflection angle Ψ is offset along the radial direction. The offset is e+e', where e is the distance from the intersection of the cone generatrix and the valve plate minor diameter end face to the rotation center after the offset, and e' is the radial distance between the rotation center and the central axis of the valve flow channel. P, P', Q, Q' are the intersection points of the right cone angle and the valve plate sealing surface when the cone angle is not deflected. C, C', D, D' are the intersection points of the cone angle and the valve plate sealing surface after rotation. From step 1, we know the equations of straight line PP', straight line QQ', straight line CC', and straight line DD'. If the thickness of the valve plate is h, then: When the cone angle is not deflected: When the cone angle is deflected: |OC|=Rcos(Ψ)-Rsin(Ψ)tan(θ-Ψ) (Formula 7) |OC'|=tan(θ-Ψ)h+Rcos(Ψ)-Rsin(Ψ)tan(θ-Ψ) (Formula 8) |OD|=Rcos(Ψ)+Rsin(Ψ)tan(θ+Ψ) (Formula 9) |OD'|=tan(θ+Ψ)h+Rcos(Ψ)+Rsin(Ψ)tan(θ+Ψ) (Formula 10) Then the radial eccentricity should be: |OD'|-|OQ'|≤e+e'≤|OP'|-|OC'| (Formula 11) In the formula, R, θ, and Ψ are known values. The range of radial eccentricity e+e' can be known from formula (11); Step 3: Design and determine the valve axial eccentricity Line GG' is perpendicular to line A'G, and line GG' intersects the axis of the rotation center with point G'. Line BB' is perpendicular to line A'B, and line BB' intersects the axis of the rotation center with point B'. The eccentricity of the rotation center to the X-axis is e'. From step 1, we know that c should meet the following conditions: |O'B'|≤c≤|O'G'| (Formula 12) After the right cone is deflected by an angle and radially eccentric, From (Formula 3) and (Formula 4), we know that: |O'B'|={tan(θ-Ψ)h+Rcos(Ψ)-Rsin(Ψ)tan(θ-Ψ)+e}tan(θ-Ψ)+h (Formula 13) |O'G'|={Rcos(Ψ)+Rsin(Ψ)tan(θ+Ψ)-e}tan(θ+Ψ) (Formula 14) Where R, θ, Ψ, and e' are all known values. Combining (Formula 12), (Formula 13), and (Formula 14), we can get the range of c, that is, the eccentricity of the rotary axis is That is, according to the following formula, the three eccentricity parameters of the butterfly valve can be obtained: angular eccentricity Ψ, radial eccentricity e+e', and axial eccentricity

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