A pipe straightening and circular blanking method

Abstract

This invention relates to a method for cutting pipes into circular openings, comprising: marking four points A1, A2, A3, and A4 circumferentially on the inner side of one end of the pipe opening, and marking four points B1, B2, B3, and B4 circumferentially on the inner side of the other end of the pipe opening; measuring the lengths of A1 and B1, A2 and B2, A3 and B3, and A4 and B4; measuring the lengths of A1 and B3, A2 and B4, A3 and B1, and A4 and B2; establishing a three-dimensional spatial coordinate system; calculating and labeling the coordinates of A1, B1, A2, B2, A3, B3, A4, and B4; determining a point E on the X-axis, and calculating the projection of point E onto line segments L1, L2, L3, and L4; and performing positional analysis relative to A1, B1, A2, B2, A3, B3, A4, and B4 respectively. Advantages: It can obtain accurate data for drawing the correct circular shape of the pipeline, reduce the error in finding the correct circular shape, improve the alignment and construction conditions, and thus improve the quality of construction, renovation and operation of pipelines.

Description

Technical Field

[0001] This invention relates to the field of oil and gas pipeline construction technology, and in particular to a method for cutting materials into the correct circular shape for pipeline openings. Background Technology

[0002] In the construction of oil and gas pipelines, it is often necessary to shape the pipe ends into specific forms. These shapes are drawn and cut based on the standard circular shape of the pipe opening. Currently, there are two main methods for drawing the standard circular shape of a pipe:

[0003] 1) The pipe wall is wrapped with a ring, and the edge formed by the ring can be considered as the positive circle of the pipe opening;

[0004] 2) Draw using a flange with an inner diameter approximately equal to the outer diameter of the pipe. Use a right-angle ruler or similar tool to make the flange plane perpendicular to the outer wall of the pipe. Draw along the flange plane on the outer wall of the pipe, which can be considered as the positive circle of the pipe.

[0005] Because the positive opening circle found by the above two methods differs significantly in shape from the actual positive opening circle, the connection gap often fails to meet the construction requirements, resulting in operation failure or forced assembly, which poses a significant safety hazard to production and operation.

[0006] Therefore, it is necessary to develop a method for cutting pipes into circular shapes at the pipe opening to overcome the aforementioned technical problems. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a method for blanking pipes with a positive opening, which effectively overcomes the defects of the prior art.

[0008] The technical solution of the present invention to solve the above-mentioned technical problems is as follows:

[0009] A method for blanking pipes with a positive opening includes the following steps:

[0010] Step 1: Mark four points (A1, A2, A3, A4) on the inside of one end of the pipe along the circumference, and mark four points (B1, B2, B3, B4) on the inside of the other end of the pipe along the circumference, so that A1 and B1, A2 and B2, A3 and B3, and A4 and B4 fall on the same straight line in the axial direction.

[0011] Step 2: Measure the lengths of line segment L1 between A1 and B1, line segment L2 between A2 and B2, line segment L3 between A3 and B3, and line segment L4 between A4 and B4; and the plane containing line segments L1 and L3 intersects the plane containing line segments L2 and L4, and the line of intersection coincides with the axis of the pipe.

[0012] Step 3: Measure the length of line segment S1 between A1 and B3, the length of line segment S2 between A2 and B4, the length of line segment S3 between A3 and B1, and the length of line segment S4 between A4 and B2.

[0013] Step 4: Establish a three-dimensional spatial coordinate system with the midpoint of the perpendicular line segment between line segments L1 and L3 as the origin. The X-axis points along the axial direction of the pipe, the Y-axis points along the radial direction of the pipe and is perpendicular to line segment L1, and the Z-axis points along the radial direction of the pipe and is perpendicular to line segment L2.

[0014] Step 5: Calculate and label the coordinates of A1, B1, A2, B2, A3, B3, A4, and B4 using the three-dimensional coordinate system and the measured line segment data.

[0015] Step 6: Determine a point E on the X-axis, calculate the projections of point E onto line segments L1, L2, L3, and L4, and denote them as F1, F2, F3, and F4, respectively.

[0016] Step 7: Using the coordinates F1, F2, F3, and F4, positional analysis can be performed with respect to A1, B1, A2, B2, A3, B3, A4, and B4 respectively, to obtain the positional relationship between the positive opening circle and each feature point in the pipe axis.

[0017] Based on the above technical solution, the present invention can be further improved as follows.

[0018] Furthermore, in step four above, the method for establishing a three-dimensional spatial coordinate system is as follows:

[0019] S11. Take four points A, B, C, and D on plane A1A3B1B3, where A and B lie on line segment L1, C and D lie on line segment L3, and the intersection of line segments AD and BC is O.

[0020] S12. Assuming the length of line segment AO is known, then OD = AD - AO;

[0021] S13. Calculate the length of BO, BO = AO * BC / AD;

[0022] S14. Calculate the length of OC, OC = BC - BO;

[0023] S15. Calculate ∠AOB using the Law of Cosines;

[0024] S16. Calculate ∠COD using the Law of Cosines;

[0025] S17. By using ∠AOB=∠COD, we obtain a system of equations and solve them to get the length of AO;

[0026] S18. Line segments AB and CD are parallel, and the vertical distance between them is the pipe diameter.

[0027] S19. In plane ABCD, specify the midpoint of the perpendicular line segment of line segment AB and line segment CD as the origin, establish a coordinate system in the X-axis direction, and use basic geometric principles to obtain the coordinates of A, B, C, and D.

[0028] S20. By using the fact that the values ​​of A2, A4, B2, and B4 in the Y-axis direction are 0, and the values ​​of A1, A3, B1, and B3 in the Z-axis direction are 0, we can obtain the coordinates of A1, B1, A2, B2, A3, B3, A4, and B4 in the established three-dimensional spatial coordinate system.

[0029] Among them, the lengths of line segments L1, L2, L3, L4, S1, S2, S3, S4, and the pipe diameter are known parameters that are measured.

[0030] Furthermore, the four points A1, A2, A3, and A4 are distributed at equal intervals along the circumference.

[0031] Furthermore, the four points A1, A2, A3, and A4 are set in a clockwise direction, with point A1 located at the 12 o'clock position.

[0032] Furthermore, in step seven above, using the coordinates F1, F2, F3, and F4, positional analysis can be performed relative to A1, B1, A2, B2, A3, B3, A4, and B4, respectively. Specifically, this includes:

[0033] S111, Calculate the length data of line segments A1F1, A2F2, A3F3, and A4F4, which are used for blanking the positive opening circle of the pipe where feature point A1 is located;

[0034] S112. Calculate the length data of line segments B1F1, B2F2, B3F3, and B4F4 for use in the blanking of the pipe opening at feature point B1.

[0035] Furthermore, the location of point E mentioned above is close to either end of the pipeline.

[0036] Furthermore, it also includes step eight: drawing the circular shape of the pipe opening.

[0037] Furthermore, it also includes step nine: cutting the pipe's positive opening circle according to the shape and coordinate data.

[0038] Furthermore, in step one above, A1, A2, A3, A4 and B1, B2, B3, B4 are aligned and marked using the highest point principle.

[0039] Furthermore, in step six above, take another point on the X-axis that is different from E, then calculate the projection of this end onto line segments L1, L2, L3, and L4, mark the projection points, and then use the method in step seven to perform analysis and verification again.

[0040] The beneficial effects of this invention are: by using the feature points on the inner wall of the pipe at both ends, the length between the feature points is measured, and relevant spatial calculations are performed in combination with the pipe wall to obtain accurate data for drawing the circular shape of the pipe opening. This can improve the alignment and construction conditions by reducing the error in finding the circular opening, thereby improving the construction quality of pipeline construction, renovation and operation. Attached Figure Description

[0041] Figure 1 This is a schematic diagram showing the distribution of pipe opening feature points and four length data involved in the pipe opening circular blanking method of the present invention.

[0042] Figure 2 This is a schematic diagram of four length measurements taken on the pipe involved in the pipe cutting method for the positive opening of the present invention.

[0043] Figure 3 This is a geometric schematic diagram illustrating the calculation principle involved in the pipe opening circular blanking method of the present invention;

[0044] Figure 4 This is a schematic diagram of the three-dimensional spatial coordinate system involved in the pipe opening circular blanking method of the present invention;

[0045] Figure 5 This is a schematic diagram of the positive opening circle involved in the pipe positive opening circle material cutting method of the present invention. Detailed Implementation

[0046] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0047] Example: Figure 1 , 2 As shown in Figures 3, 4, and 5, the pipe cutting method for the positive opening of the pipe in this embodiment includes the following steps:

[0048] Step 1: Mark four points (A1, A2, A3, A4) circumferentially on the inside of one end of the pipe opening, and mark four points (B1, B2, B3, B4) circumferentially on the inside of the other end of the pipe opening, ensuring that A1 and B1, A2 and B2, A3 and B3, and A4 and B4 fall on the same straight line axially; wherein, A1, A2, A3, A4 and B1, B2, B3, B4 are aligned and marked using the principle of the highest point;

[0049] Step 2: Measure the lengths of line segment L1 between A1 and B1, line segment L2 between A2 and B2, line segment L3 between A3 and B3, and line segment L4 between A4 and B4; and the plane containing line segments L1 and L3 intersects the plane containing line segments L2 and L4, and the line of intersection coincides with the axis of the pipe.

[0050] Step 3: Measure the length of line segment S1 between A1 and B3, the length of line segment S2 between A2 and B4, the length of line segment S3 between A3 and B1, and the length of line segment S4 between A4 and B2.

[0051] Step 4: Establish a three-dimensional spatial coordinate system with the midpoint of the perpendicular line segment between line segments L1 and L3 as the origin. The X-axis points along the axial direction of the pipe, the Y-axis points along the radial direction of the pipe and is perpendicular to line segment L1, and the Z-axis points along the radial direction of the pipe and is perpendicular to line segment L2. The method for establishing the three-dimensional spatial coordinate system is as follows:

[0052] S11. Take four points A, B, C, and D on plane A1A3B1B3, where A and B lie on line segment L1, C and D lie on line segment L3, and the intersection of line segments AD and BC is O.

[0053] S12. Assuming the length of line segment AO is known, then OD = AD - AO;

[0054] S13. Calculate the length of BO, BO = AO * BC / AD;

[0055] S14. Calculate the length of OC, OC = BC - BO;

[0056] S15. Calculate ∠AOB using the Law of Cosines;

[0057] S16. Calculate ∠COD using the Law of Cosines;

[0058] S17. By using ∠AOB=∠COD, we obtain a system of equations and solve them to get the length of AO;

[0059] S18. Line segments AB and CD are parallel, and the vertical distance between them is the pipe diameter.

[0060] S19. In plane ABCD, specify the midpoint of the perpendicular line segment of line segment AB and line segment CD as the origin, establish a coordinate system in the X-axis direction, and use basic geometric principles to obtain the coordinates of A, B, C, and D.

[0061] S20. By using the fact that the values ​​of A2, A4, B2, and B4 in the Y-axis direction are 0, and the values ​​of A1, A3, B1, and B3 in the Z-axis direction are 0, we can obtain the coordinates of A1, B1, A2, B2, A3, B3, A4, and B4 in the established three-dimensional spatial coordinate system.

[0062] Among them, the lengths of line segments L1, L2, L3, L4, S1, S2, S3, S4, and the pipe diameter are known parameters that are measured;

[0063] Step 5: Calculate and label the coordinates of A1, B1, A2, B2, A3, B3, A4, and B4 using the three-dimensional coordinate system and the measured line segment data.

[0064] Step 6: Determine a point E on the X-axis, calculate the projections of point E onto line segments L1, L2, L3, and L4, and denote them as F1, F2, F3, and F4, respectively.

[0065] Step 7: Using the coordinates F1, F2, F3, and F4, positional analysis can be performed relative to A1, B1, A2, B2, A3, B3, A4, and B4 respectively to obtain the positional relationship between the positive opening circle and each feature point along the pipe axis, as follows:

[0066] S111, Calculate the length data of line segments A1F1, A2F2, A3F3, and A4F4, which are used for blanking the positive opening circle of the pipe where feature point A1 is located;

[0067] S112. Calculate the length data of line segments B1F1, B2F2, B3F3, and B4F4 for use in the blanking of the pipe opening at feature point B1.

[0068] Example 2

[0069] The pipe cutting method for the positive opening of the pipe in this embodiment includes the following steps:

[0070] Step 1: Mark four points (A1, A2, A3, A4) circumferentially on the inside of one end of the pipe opening, and mark four points (B1, B2, B3, B4) circumferentially on the inside of the other end of the pipe opening, ensuring that A1 and B1, A2 and B2, A3 and B3, and A4 and B4 fall on the same straight line axially; wherein, A1, A2, A3, A4 and B1, B2, B3, B4 are aligned and marked using the principle of the highest point;

[0071] Step 2: Measure the lengths of line segment L1 between A1 and B1, line segment L2 between A2 and B2, line segment L3 between A3 and B3, and line segment L4 between A4 and B4; and the plane containing line segments L1 and L3 intersects the plane containing line segments L2 and L4, and the line of intersection coincides with the axis of the pipe.

[0072] Step 3: Measure the length of line segment S1 between A1 and B3, the length of line segment S2 between A2 and B4, the length of line segment S3 between A3 and B1, and the length of line segment S4 between A4 and B2.

[0073] Step 4: Establish a three-dimensional spatial coordinate system with the midpoint of the perpendicular line segment between line segments L1 and L3 as the origin. The X-axis points along the axial direction of the pipe, the Y-axis points along the radial direction of the pipe and is perpendicular to line segment L1, and the Z-axis points along the radial direction of the pipe and is perpendicular to line segment L2. The method for establishing the three-dimensional spatial coordinate system is as follows:

[0074] S11. Take four points A, B, C, and D on plane A1A3B1B3, where A and B lie on line segment L1, C and D lie on line segment L3, and the intersection of line segments AD and BC is O.

[0075] S12. Assuming the length of line segment AO is known, then OD = AD - AO;

[0076] S13. Calculate the length of BO, BO = AO * BC / AD;

[0077] S14. Calculate the length of OC, OC = BC - BO;

[0078] S15. Calculate ∠AOB using the Law of Cosines;

[0079] S16. Calculate ∠COD using the Law of Cosines;

[0080] S17. By using ∠AOB=∠COD, we obtain a system of equations and solve them to get the length of AO;

[0081] S18. Line segments AB and CD are parallel, and the vertical distance between them is the pipe diameter.

[0082] S19. In plane ABCD, specify the midpoint of the perpendicular line segment of line segment AB and line segment CD as the origin, establish a coordinate system in the X-axis direction, and use basic geometric principles to obtain the coordinates of A, B, C, and D.

[0083] S20. By using the fact that the values ​​of A2, A4, B2, and B4 in the Y-axis direction are 0, and the values ​​of A1, A3, B1, and B3 in the Z-axis direction are 0, we can obtain the coordinates of A1, B1, A2, B2, A3, B3, A4, and B4 in the established three-dimensional spatial coordinate system.

[0084] Among them, the lengths of line segments L1, L2, L3, L4, S1, S2, S3, S4, and the pipe diameter are known parameters that are measured;

[0085] Step 5: Calculate and label the coordinates of A1, B1, A2, B2, A3, B3, A4, and B4 using the three-dimensional coordinate system and the measured line segment data.

[0086] Step 6: Determine a point E on the X-axis, calculate the projections of point E onto line segments L1, L2, L3, and L4, and denote them as F1, F2, F3, and F4, respectively.

[0087] Step 7: Using the coordinates F1, F2, F3, and F4, positional analysis can be performed relative to A1, B1, A2, B2, A3, B3, A4, and B4 respectively to obtain the positional relationship between the positive opening circle and each feature point along the pipe axis, as follows:

[0088] S111, Calculate the length data of line segments A1F1, A2F2, A3F3, and A4F4, which are used for blanking the positive opening circle of the pipe where feature point A1 is located;

[0089] S112. Calculate the length data of line segments B1F1, B2F2, B3F3, and B4F4 for use in the blanking of the pipe opening at feature point B1.

[0090] Step 8: Draw the circular shape of the pipe opening.

[0091] Example 3

[0092] The pipe cutting method for the positive opening of the pipe in this embodiment includes the following steps:

[0093] Step 1: Mark four points (A1, A2, A3, A4) circumferentially on the inside of one end of the pipe opening, and mark four points (B1, B2, B3, B4) circumferentially on the inside of the other end of the pipe opening, ensuring that A1 and B1, A2 and B2, A3 and B3, and A4 and B4 fall on the same straight line axially; wherein, A1, A2, A3, A4 and B1, B2, B3, B4 are aligned and marked using the principle of the highest point;

[0094] Step 2: Measure the lengths of line segment L1 between A1 and B1, line segment L2 between A2 and B2, line segment L3 between A3 and B3, and line segment L4 between A4 and B4; and the plane containing line segments L1 and L3 intersects the plane containing line segments L2 and L4, and the line of intersection coincides with the axis of the pipe.

[0095] Step 3: Measure the length of line segment S1 between A1 and B3, the length of line segment S2 between A2 and B4, the length of line segment S3 between A3 and B1, and the length of line segment S4 between A4 and B2.

[0096] Step 4: Establish a three-dimensional spatial coordinate system with the midpoint of the perpendicular line segment between line segments L1 and L3 as the origin. The X-axis points along the axial direction of the pipe, the Y-axis points along the radial direction of the pipe and is perpendicular to line segment L1, and the Z-axis points along the radial direction of the pipe and is perpendicular to line segment L2. The method for establishing the three-dimensional spatial coordinate system is as follows:

[0097] S11. Take four points A, B, C, and D on plane A1A3B1B3, where A and B lie on line segment L1, C and D lie on line segment L3, and the intersection of line segments AD and BC is O.

[0098] S12. Assuming the length of line segment AO is known, then OD = AD - AO;

[0099] S13. Calculate the length of BO, BO = AO * BC / AD;

[0100] S14. Calculate the length of OC, OC = BC - BO;

[0101] S15. Calculate ∠AOB using the Law of Cosines;

[0102] S16. Calculate ∠COD using the Law of Cosines;

[0103] S17. By using ∠AOB=∠COD, we obtain a system of equations and solve them to get the length of AO;

[0104] S18. Line segments AB and CD are parallel, and the vertical distance between them is the pipe diameter.

[0105] S19. In plane ABCD, specify the midpoint of the perpendicular line segment of line segment AB and line segment CD as the origin, establish a coordinate system in the X-axis direction, and use basic geometric principles to obtain the coordinates of A, B, C, and D.

[0106] S20. By using the fact that the values ​​of A2, A4, B2, and B4 in the Y-axis direction are 0, and the values ​​of A1, A3, B1, and B3 in the Z-axis direction are 0, we can obtain the coordinates of A1, B1, A2, B2, A3, B3, A4, and B4 in the established three-dimensional spatial coordinate system.

[0107] Among them, the lengths of line segments L1, L2, L3, L4, S1, S2, S3, S4, and the pipe diameter are known parameters that are measured;

[0108] Step 5: Calculate and label the coordinates of A1, B1, A2, B2, A3, B3, A4, and B4 using the three-dimensional coordinate system and the measured line segment data.

[0109] Step 6: Determine a point E on the X-axis, calculate the projections of point E onto line segments L1, L2, L3, and L4, and denote them as F1, F2, F3, and F4, respectively.

[0110] Step 7: Using the coordinates F1, F2, F3, and F4, positional analysis can be performed relative to A1, B1, A2, B2, A3, B3, A4, and B4 respectively to obtain the positional relationship between the positive opening circle and each feature point along the pipe axis, as follows:

[0111] S111, Calculate the length data of line segments A1F1, A2F2, A3F3, and A4F4, which are used for blanking the positive opening circle of the pipe where feature point A1 is located;

[0112] S112. Calculate the length data of line segments B1F1, B2F2, B3F3, and B4F4 for use in the blanking of the positive opening circle of the pipe where feature point B1 is located.

[0113] Step 8: Draw the circular shape of the pipe opening;

[0114] Step 9: Cut the pipe's central circle according to its shape and coordinate data.

[0115] Example 4

[0116] In this embodiment, based on embodiments 1, 2, and 3, in step six, another point different from E is selected on the X-axis. Then, the projection of this point onto line segments L1, L2, L3, and L4 is calculated, and the projection point is marked. Then, the method in step seven is used for further analysis and verification.

[0117] The rest is the same as in Examples 1, 2, and 3.

[0118] It is particularly important to emphasize that, based on the above embodiments 1, 2, and 3, the four points A1, A2, A3, and A4 are distributed at equal intervals along the circumference. That is, A1 and A2 are separated by a 90° central angle, A3 and A2 are separated by a 90° central angle, A4 and A3 are separated by a 90° central angle, and A1 and A4 are separated by a 90° central angle.

[0119] It is important to emphasize that the four points A1, A2, A3, and A4 are set in a clockwise direction (from the perspective of looking directly at one end of the pipe), and point A1 is at the 12 o'clock position.

[0120] It is important to emphasize that point E is located near either end of the pipe.

[0121] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0122] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0123] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0124] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0125] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0126] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for blanking pipes with a positive opening, characterized in that, Includes the following steps: Step 1: Mark four points A1, A2, A3, and A4 circumferentially on the inside of one end of the pipe opening, and mark four points B1, B2, B3, and B4 circumferentially on the inside of the other end of the pipe opening, so that A1 and B1, A2 and B2, A3 and B3, and A4 and B4 fall on the same straight line in the axial direction. Step 2: Measure the lengths of line segment L1 between A1 and B1, line segment L2 between A2 and B2, line segment L3 between A3 and B3, and line segment L4 between A4 and B4; and the plane containing line segments L1 and L3 intersects the plane containing line segments L2 and L4, and the line of intersection coincides with the axis of the pipe. Step 3: Measure the length of line segment S1 between A1 and B3, the length of line segment S2 between A2 and B4, the length of line segment S3 between A3 and B1, and the length of line segment S4 between A4 and B2. Step 4: Establish a three-dimensional spatial coordinate system with the midpoint of the perpendicular line segment between line segments L1 and L3 as the origin. The X-axis points along the axial direction of the pipe, the Y-axis points along the radial direction of the pipe and is perpendicular to line segment L1, and the Z-axis points along the radial direction of the pipe and is perpendicular to line segment L2. Step 5: Calculate and label the coordinates of A1, B1, A2, B2, A3, B3, A4, and B4 using the three-dimensional coordinate system and the measured line segment data. Step 6: Determine a point E on the X-axis, calculate the projections of point E onto line segments L1, L2, L3, and L4, and denote them as F1, F2, F3, and F4, respectively. Step 7: Using the coordinates F1, F2, F3, and F4, positional analysis can be performed with respect to A1, B1, A2, B2, A3, B3, A4, and B4 respectively to obtain the positional relationship between the positive opening circle and each feature point in the pipe axis. In step four, the method for establishing a three-dimensional spatial coordinate system is as follows: S11. Take four points A, B, C, and D on plane A1A3B1B3, where A and B lie on line segment L1, C and D lie on line segment L3, and the intersection of line segments AD and BC is O. S12. Assuming the length of line segment AO is known, then OD = AD - AO; S13. Calculate the length of BO, BO=AO*BC / AD; S14. Calculate the length of OC, OC = BC - BO; S15. Calculate ∠AOB using the Law of Cosines; S16. Calculate ∠COD using the Law of Cosines; S17. By using ∠AOB=∠COD, we obtain a system of equations and solve them to get the length of AO; S18. Line segments AB and CD are parallel, and the vertical distance between them is the pipe diameter. S19. In plane ABCD, specify the midpoint of the perpendicular line segment of line segment AB and line segment CD as the origin, establish a coordinate system in the X-axis direction, and use basic geometric principles to obtain the coordinates of A, B, C, and D. S20. Using the fact that the values ​​of A2, A4, B2, and B4 in the Y-axis direction are 0, and the values ​​of A1, A3, B1, and B3 in the Z-axis direction are 0, we obtain the coordinates of A1, B1, A2, B2, A3, B3, A4, and B4 in the established three-dimensional spatial coordinate system. Among them, the lengths of line segments L1, L2, L3, L4, S1, S2, S3, S4, and the pipe diameter are known parameters that are measured; The four points A1, A2, A3, and A4 are distributed at equal intervals along the circumference; In step seven, using the coordinates F1, F2, F3, and F4, positional analysis can be performed relative to A1, B1, A2, B2, A3, B3, A4, and B4, respectively. Specifically, this includes: S111, Calculate the length data of line segments A1F1, A2F2, A3F3, and A4F4, which are used for blanking the positive opening circle of the pipe where feature point A1 is located; S112. Calculate the length data of line segments B1F1, B2F2, B3F3, and B4F4 for use in the blanking of the pipe opening at feature point B1.

2. The method for cutting pipes into circular openings according to claim 1, characterized in that: The four points A1, A2, A3, and A4 are arranged in a clockwise direction, with point A1 located at the 12 o'clock position.

3. The method for cutting pipes into circular openings according to claim 1, characterized in that: Point E is located near either end of the pipeline.

4. A method for blanking pipes at the positive opening according to any one of claims 1 to 3, characterized in that, It also includes step eight, drawing the circular shape of the pipe opening.

5. The method for cutting pipes into circular openings according to claim 4, characterized in that, It also includes step nine, cutting the pipe's central circle according to its shape and coordinate data.

6. A method for blanking pipes at the circumference according to any one of claims 1 to 3, characterized in that: In step one, A1, A2, A3, A4 are aligned with B1, B2, B3, B4 and marked using the highest point principle.

7. The method for cutting pipes into circular openings according to claim 6, characterized in that: In step six, another point different from E is selected on the X-axis. The projection of this point onto line segments L1, L2, L3, and L4 is calculated, and the projection points are marked. Then, the method in step seven is used for further analysis and verification.

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