Method for parallel offsetting of large diameter pipes

Abstract

This disclosure relates to a method for parallel offsetting of a large-diameter pipeline, comprising the following steps: making two parallel oblique cuts on the pipeline to form a first pipe segment, a second pipe segment, and an obliquely cut pipe segment located between the first and second pipe segments; rotating the obliquely cut pipe segment 180° around its axis in the circumferential direction to tilt the obliquely cut pipe segment, and connecting one end face of the obliquely cut pipe segment to the cut surface of the first pipe segment, and connecting the other end face of the obliquely cut pipe segment to the cut surface of the second pipe segment, so that the second pipe segment is parallelly offset from a first position to a second position. In this way, the oblique cutting and deflection method is used to achieve parallel offsetting of the pipeline, simplifying the parallel offsetting of large-diameter pipelines. No additional pipeline is required; it can be directly cut and installed by changing the angle, saving labor and materials, and significantly improving operational efficiency.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of pipe connection, in particular to a parallel offset operation method of large-diameter pipes. BACKGROUND

[0002] With the increasing application of large-diameter pipes in the industrial field, the spatial misalignment problem in field installation and maintenance is increasing, which brings hidden dangers to the safe operation of the pipes. Since it is difficult to adjust the spatial angle of the large-diameter pipe by cold bending or hot bending, when the spatial parallel offset misalignment is needed, the processing is relatively complex.

[0003] In related technologies, the connection technology of spatial misalignment equal-diameter pipes mainly includes the following methods: a field measurement method based on a non-contact measurement device-total station, a pipe opening center positioning method, a double 45° reverse bending joint method, a deflection angle and offset measurement positioning method, and a double bending joint method with a straight section in the middle.

[0004] Among them, the field measurement method based on the non-contact measurement device-total station requires more measurement instruments and operation space, and needs to solve various equations, which is very complex to calculate; the pipe opening center positioning method needs to find the pipe center first, which is difficult to determine, resulting in a large measurement error of the final cutting; the double 45° bending joint method with a small straight pipe in the middle is mainly used for water supply plastic pipes, which needs four connections and can meet different offset amounts, but when the offset amount is small, the gap of the straight pipe in the middle is very small, which is not convenient for connection, and the overall length of the structure is relatively long, which cannot balance the overall length of the offset bending joint and the complexity of the production mold structure; patent CN114459321A discloses a connection method for spatial misalignment equal-diameter pipes based on measurement of deflection angle and offset, which has a large amount of calculation work and is not easy to master in conventional construction; patent CN213598809U also discloses an offset bending joint and a pipe system, which is not suitable for large-diameter pipes with small offset.

[0005] Therefore, there is an urgent need for a simplified calculation and operation method for parallel offset of large-diameter circular pipes. SUMMARY

[0006] The purpose of the present disclosure is to provide a parallel offset operation method of large-diameter pipes to at least partially solve the problems existing in the related art.

[0007] To achieve the above purpose, the present disclosure provides a parallel offset operation method of large-diameter pipes, comprising the following steps:

[0008] The pipe is cut twice in parallel to form a first pipe section, a second pipe section, and a cut pipe section between the first pipe section and the second pipe section;

[0009] The beveling pipe segment is turned 180° around the axis in the circumferential direction, the beveling pipe segment is inclined, one end surface of the beveling pipe segment is connected with the cutting surface of the first pipe segment, and the other end surface of the beveling pipe segment is connected with the cutting surface of the second pipe segment, so that the second pipe segment is offset from the first position to the second position.

[0010] Optionally, before the pipe is beveled twice in parallel, the beveling projection length x of the beveling pipe segment is determined, and the step of calculating the beveling projection length x of the beveling pipe segment comprises:

[0011] The diameter d of the pipe is obtained.

[0012] The transverse offset h of the second pipe segment is obtained.

[0013] The length l of the beveling pipe segment is obtained.

[0014] The beveling projection length x of the beveling pipe segment is calculated by the formula

[0015] Optionally, the axial shortening amount a of the pipe after parallel offset is calculated to confirm the axial compensation amount to be provided.

[0016] Optionally, the step of calculating the axial shortening amount a comprises:

[0017] The diameter d of the pipe is obtained.

[0018] The transverse offset h of the second pipe segment is obtained.

[0019] The axial shortening amount a of the pipe after parallel offset is calculated by the formula

[0020] Optionally, according to the calculated axial shortening amount a, a weld compensation or an expansion joint is added to the pipe in the axial direction.

[0021] Optionally, before the pipe is beveled twice in parallel, the beveling positioning size of the pipe needs to be calculated, and the step of calculation comprises:

[0022] A circle O with a diameter d is drawn, and a diameter UV is drawn on the circle.

[0023] A plurality of equal division points are drawn on the circle O.

[0024] A projection line segment DN is drawn on one side of the circle O.

[0025] A line segment CN perpendicular to DN is drawn, the length of the line segment CN is x, and the line segment CD is connected.

[0026] A perpendicular line is drawn through each of the equal division points on one side of the circle O to the line segment DN.​​

[0027] Mark and record the length of the perpendicular segment between each perpendicular clamp and the line segment CD and DN.

[0028] Optionally, after calculating the beveling positioning size, the outer surface of the pipe needs to be beveled and positioned, and the positioning step comprises:

[0029] Determining the vertices U, V of the beveling reference position on the pipe;

[0030] Marking the reference circle with U, V as the vertices on the outer surface of the pipe, and the plane where the reference circle is located is perpendicular to the axis of the pipe;

[0031] Marking a plurality of equidistant points containing vertices U, V on the reference circle;

[0032] According to the recorded length of the perpendicular segment between each perpendicular clamp and the line segment CD and DN, mark the position of each beveling positioning point on one side of the reference circle according to the length of each perpendicular segment corresponding to each equidistant point;

[0033] Connecting the beveling positioning points in sequence to form a first beveling cross-sectional circumference;

[0034] According to the length l of the beveling pipe segment, mark a second beveling cross-sectional circumference parallel to the first beveling cross-sectional circumference on the outer surface of the pipe.

[0035] Optionally, after beveling and positioning the outer surface of the pipe,

[0036] Marking two vertex positions on the first beveling cross-sectional circumference to position when the beveling pipe segment is installed in reverse;

[0037] Taking safety measures such as pipe working medium insulation, discharge and support and the like;

[0038] Cutting the pipe at the marked positions of the first beveling cross-sectional circumference and the second beveling cross-sectional circumference.

[0039] Optionally, after beveling the pipe twice in parallel, hoist the beveling pipe segment away, remove the second pipe segment, and then move the second pipe segment from the first position to the second position.

[0040] Optionally, the number of equidistant points is even.

[0041] The above technical solution uses the oblique cutting and deflection method to achieve parallel offset of the pipeline. This can be achieved by making two parallel oblique cuts on the pipeline and rotating the obliquely cut section 180° around the axis along the circumference. The obliquely cut section will tilt as a whole, and the second section will be offset from the first position to the second position so that the two end faces of the obliquely cut section match and connect with the cut surfaces of the first and second sections respectively. This simplifies the parallel offset of large-diameter pipelines, eliminates the need for additional pipelines, and allows for direct cutting and angle adjustment for installation, saving labor and materials and significantly improving work efficiency.

[0042] Other features and advantages of this disclosure will be described in detail in the following detailed description section. Attached Figure Description

[0043] The accompanying drawings are provided to further illustrate the present disclosure and form part of the specification. They are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation thereof. In the drawings:

[0044] Figure 1 This is a before-and-after comparison of the parallel offset of a large-diameter pipe provided in an exemplary embodiment of this disclosure;

[0045] Figure 2 This is a schematic diagram of the oblique positioning principle of a pipe provided in an exemplary embodiment of this disclosure.

[0046] Explanation of reference numerals in the attached figures

[0047] 1. First pipe section 2. Second pipe section

[0048] 3 oblique pipe sections Detailed Implementation

[0049] The specific embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this disclosure.

[0050] In this disclosure, unless otherwise stated, directional terms such as "up" and "down" are used. Figure 1 The drawing orientation is shown. "Inner" and "outer" refer to the inner and outer contours of the corresponding components. Furthermore, the terms "first," "second," etc., used in this disclosure are for distinguishing one element from another and do not indicate sequence or importance. When the following description refers to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements.

[0051] refer to Figure 1The present disclosure provides a large-diameter pipeline parallel offset operation method, which can include the following steps: twice parallel beveling of the pipeline to form a first pipe segment 1, a second pipe segment 2 and a beveled pipe segment 3 between the first pipe segment 1 and the second pipe segment 2, and specifically, the parallel beveling refers to that the two beveling planes are parallel to each other; the beveled pipe segment 3 is turned 180° around the axis in the circumferential direction, at this time, as shown in Figure 1 FIG. 6, the beveled pipe segment 3 is moved from ABCD to FEDC, the beveled pipe segment 3 is tilted, one end surface of the beveled pipe segment 3 is connected with the beveling plane of the first pipe segment 1, and the other end surface of the beveled pipe segment 3 is connected with the beveling plane of the second pipe segment 2, so that the second pipe segment 2 is parallel offset from the first position 2' to the second position 2'', and the parallel offset of the pipeline is realized. Specifically, the cutting and connection of the pipeline can be realized by gas cutting, adhesion and the like.

[0052] By the above technical solution, the parallel offset of the pipeline is realized by the beveling and deflection method. The pipeline is twice parallel beveled, and after the beveled pipe segment is turned 180° around the axis in the circumferential direction, the beveled pipe segment is tilted as a whole, the second pipe segment is parallel offset from the first position to the second position, so that the two end surfaces of the beveled pipe segment are connected with the beveling planes of the first pipe segment and the second pipe segment respectively, the parallel offset of the large-diameter pipeline is simplified, no additional pipeline is needed, and the pipeline can be directly cut and installed by changing the angle, which saves labor and materials and significantly improves the operation efficiency. The pipeline deflected by the method has small flow resistance, can eliminate the radial internal stress of the pipeline, and is helpful to reduce system loss and prolong equipment life. The whole process does not need special instruments and equipment, and is easy for users to master.

[0053] It should be noted that the above method is suitable for the parallel offset of large-diameter pipelines, of course, the above method can also be used for the parallel offset of small-diameter pipelines and solid straight cylindrical materials, and the present disclosure does not limit the diameter of the pipeline, which all belong to the protection scope of the present disclosure.

[0054] In order to ensure that the cuts of the pipeline are closely fitted, the size of the beveling needs to be accurately calculated. Before the pipeline is twice parallel beveled, the beveling projection length x of the beveled pipe segment 3 is determined, and the step of calculating the beveling projection length x of the beveled pipe segment 3 can include: obtaining the diameter d of the pipeline; obtaining the transverse offset h of the second pipe segment 2; obtaining the length l of the beveled pipe segment 3, it should be emphasized that l is as long as possible within the allowable range of construction space, so that the deflection angle of the beveled pipe segment 3 is as small as possible; and the beveling projection length x of the beveled pipe segment 3 is calculated by the formula It should be noted that the above-mentioned "projection" refers to that a projection line passes through a point or other objects, projects to a selected projection plane, and the figure obtained on the plane is the projection of the point or object.

[0055] AsFigure 1 As shown, the pipe diameter is d (DN), parallelogram ABCD is the obliquely cut pipe segment 3, and the length of obliquely cut pipe segment 3 is l (BC). After the cut obliquely cut pipe segment 3 is rotated 180° around the axis and connected to the cut surfaces of the first pipe segment 1 and the second pipe segment 2 respectively, its position becomes parallelogram FEDC. Given that the actual required lateral offset of the pipe is h (FM), the oblique cut dimension can be determined by finding x (CN). The calculation principle of the x value is as follows:

[0056] According to the parallelogram principle:

[0057] △CBF is an isosceles triangle, and △CBF∽△GCD, △CMF∽△GND

[0058]

[0059] According to the Pythagorean theorem, q 2 =h 2 +b 2

[0060]

[0061] ∵△CMF∽△GND

[0062]

[0063]

[0064] Substituting the values ​​of d, h, and l will yield the value of x.

[0065] This disclosure derives equation (1) using plane geometry principles, clarifying the functional relationship between the oblique projection length x, diameter d, lateral offset h, and oblique pipe segment length l. Precise positioning and cutting are performed based on the calculated oblique dimensions, eliminating the need for complex calculations and resulting in higher efficiency.

[0066] If d and h are constant, the relationship between l and x can also be determined:

[0067]

[0068] As an exemplary embodiment of this disclosure, after the pipe is offset, the axial dimension of the entire pipe will become shorter due to the tilting of the oblique pipe segment 3. Therefore, it is necessary to calculate the axial shortening amount 'a' after the pipe is offset in parallel in order to determine the amount of axial compensation that needs to be provided.

[0069] Furthermore, the steps for calculating the axial shortening a may include: obtaining the pipe diameter d; obtaining the lateral offset h of the second pipe segment 2; and using the formula... Calculate the axial shortening 'a' after the pipe is parallelly offset. The principle for calculating the value of 'a' is as follows:

[0070] ∵△BMF∽△CND

[0071]

[0072] Substituting the values ​​of d, h, and x will yield the value of a.

[0073] Equation (3) derived using the above method clarifies the functional relationship between a and x. The operator can measure the pipe diameter d, lateral offset h, and oblique cut section length l on-site, determine the oblique cut projection length x according to equation (1), and then check the axial shortening a according to equation (3). This disclosure can use the above formulas to manually calculate each dimension, or it can write equations (1), (2), and (3) into software to automate the data calculation.

[0074] Specifically, based on the calculated axial shortening a (i.e., the compensation amount in the axial direction of the pipe), the actual axial shortening a is usually very small and can be compensated by the weld width. If necessary, additional pipe material can be welded or expansion joints can be installed.

[0075] In some embodiments, reference Figure 2 Before performing two parallel oblique cuts on the pipeline, the oblique cut positioning dimensions of the pipeline need to be calculated. The calculation steps may include: drawing a circle O with a diameter of d, and drawing a diameter UV on the circle. Specifically, the circle O can be drawn in CAD software or hand-drawn directly on paper, which is not limited here; making multiple equal division points on the circumference of the circle O; drawing a projection line segment DN on one side of the circle O, that is, drawing a projection line segment DN on half of the arc of the circle O; drawing a line segment CN ⊥DN, with a length of x, and connecting the line segment CD; drawing perpendicular lines from each of the equal division points on one side of the circle O to the line segment DN; marking and recording the length of the perpendicular line segment between the line segment CD and the line segment DN, which determines the position of each oblique cut positioning point. The circle and the reference circumference equal division points are drawn using CAD or other software or manual methods. The equal division point projection positioning method provided in this disclosure is simple and easy to operate, reducing the workload of on-site surveying. Alternatively, other instruments and equipment or methods other than projection methods can be used to determine the positioning points of the oblique cut. This disclosure does not limit this method, and all such methods fall within the protection scope of this disclosure.

[0076] Further, after calculating the oblique cutting positioning dimensions, it is necessary to perform oblique cutting positioning on the outer surface of the pipe. The positioning steps may include: determining the vertices U and V of the oblique cutting reference position on the pipe; marking a reference circle (line segment DN) with U and V as vertices on the outer surface of the pipe, with the plane of the reference circle perpendicular to the axis of the pipe; marking multiple equal division points including vertices U and V on the circumference of the reference circle; marking the position of each oblique cutting positioning point on one side of the oblique cutting of the reference circle according to the length of each perpendicular line segment corresponding to each marked equal division point; connecting each oblique cutting positioning point in sequence to form the first oblique cutting section circumference (line segment CD); and marking the second oblique cutting section circumference (line segment AB) parallel to the first oblique cutting section circumference on the outer surface of the pipe according to the length l of the oblique cutting pipe segment 3.

[0077] Furthermore, after obliquely positioning the outer surface of the pipe, mark the positions of the upper and lower vertices U and V on the circumference of the first oblique section to facilitate positioning during the inverted installation of the oblique pipe section 3; implement safety measures such as isolation, release, and support of the working medium inside the pipe; specifically, flammable, explosive, and corrosive working media need to be replaced, flushed, and tested; and cut the pipe at the marked positions on the circumferences of the first and second oblique sections.

[0078] The process involves making two parallel oblique cuts to the pipeline, then lifting off the obliquely cut pipe section 3 (parallelogram ABCD), removing the second pipe section 2, and then moving the second pipe section 2 from the first position to the second position. After rotating the obliquely cut pipe section 3 180° around its axis, the tilt angle is adjusted so that one end of the obliquely cut pipe section 3 aligns with the circumference of the first obliquely cut section of the first pipe section 1, and the other end aligns with the circumference of the second obliquely cut section of the offset second pipe section 2, thus achieving pipeline offset.

[0079] Given the pipe diameter d, the length l of the obliquely cut pipe section 3, and the lateral offset h, this scheme calculates the obliquely cut projection length x and determines the position of each positioning point on the obliquely cut surface using the plane projection method. By performing two parallel oblique cuts and installing the obliquely cut pipe section 3 in the opposite direction, the parallel offset of the large-diameter pipe is simplified, significantly improving the work efficiency.

[0080] In the embodiments of this disclosure, the number of division points is even, and should preferably be consistent with the number of reference points such as flange bolt holes of the pipeline.

[0081] The preferred embodiments of this disclosure have been described in detail above with reference to the accompanying drawings. However, this disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, and these simple modifications all fall within the protection scope of this disclosure.

[0082] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0083] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. A method for parallel offsetting of a large-diameter pipe, characterized in that, Includes the following steps: The pipe is cut twice in parallel oblique angles to form a first pipe segment, a second pipe segment, and an obliquely cut pipe segment located between the first pipe segment and the second pipe segment; The obliquely cut pipe segment is rotated 180° around the axis along the circumferential direction to make the obliquely cut pipe segment tilted, and one end face of the obliquely cut pipe segment is connected to the cut surface of the first pipe segment, and the other end face of the obliquely cut pipe segment is connected to the cut surface of the second pipe segment, so that the second pipe segment is offset parallel to the second position from the first position.

2. The method for parallel offsetting of a large-diameter pipeline according to claim 1, characterized in that, Before making two parallel oblique cuts to the pipe, the oblique projection length x of the obliquely cut pipe segment is determined. The steps for calculating the oblique projection length x of the obliquely cut pipe segment include: Obtain the diameter d of the pipe; Obtain the lateral offset h of the second pipe segment; Obtain the length l of the obliquely cut pipe segment; Through formula Calculate the oblique projection length x of the obliquely cut pipe segment.

3. The method for parallel offsetting of a large-diameter pipeline according to claim 2, characterized in that, Calculate the axial shortening 'a' after the pipeline is offset parallel to determine the amount of axial compensation required.

4. The method for parallel offsetting of a large-diameter pipeline according to claim 3, characterized in that, The steps for calculating the axial shortening a include: Obtain the diameter d of the pipe; Obtain the lateral offset h of the second pipe segment; Through formula Calculate the axial shortening a after the pipeline is offset parallel.

5. The method for parallel offsetting of a large-diameter pipeline according to claim 4, characterized in that, Based on the calculated axial shortening 'a', compensation is made along the axial direction of the pipe by weld or by adding an expansion joint.

6. The method for parallel offsetting of a large-diameter pipeline according to claim 2, characterized in that, Before making two parallel oblique cuts to the pipe, it is necessary to calculate the oblique cut positioning dimensions of the pipe. The calculation steps include: Draw a circle O with diameter d, and then draw a diameter UV on the circle; Divide circle O into multiple equal parts; Draw the projection line segment DN on one side of circle O; Construct line segment CN⊥DN, with length CN of length x, and connect line segment CD; Draw perpendicular lines from each of the aforementioned dividing points on one side of circle O to line segment DN; Label and record the length of each perpendicular segment between line segment CD and line segment DN.

7. The method for parallel offsetting of a large-diameter pipeline according to claim 6, characterized in that, After calculating the oblique cutting positioning dimensions, the outer surface of the pipe needs to be obliquely cut for positioning. The positioning steps include: Determine the vertices U and V of the oblique cutting reference position on the pipe; Mark a reference circle with vertices U and V on the outer surface of the pipe, and the plane containing the reference circle is perpendicular to the axis of the pipe; Mark multiple equally divided points, including vertices U and V, on the reference circle; Based on the recorded length of the perpendicular segment between line segment CD and line segment DN, the positions of each oblique positioning point are marked on one side of the reference circle according to the length of each perpendicular segment corresponding to each of the equal division points. The oblique positioning points are connected sequentially to form the circumference of the first oblique section; Based on the length l of the obliquely cut pipe section, a second obliquely cut section circumference is marked on the outer surface of the pipe, which is parallel to the circumference of the first obliquely cut section.

8. The method for parallel offsetting of a large-diameter pipeline according to claim 7, characterized in that, After obliquely positioning the outer surface of the pipe. Two vertex positions are marked on the circumference of the first oblique section to facilitate positioning during the inverted installation of the oblique pipe section; Implement safety measures such as isolation, release, and support of the working medium inside the pipeline; The pipe is cut at the marked positions on the circumference of the first oblique section and the circumference of the second oblique section.

9. The method for parallel offsetting of a large-diameter pipe according to claim 1 or 8, characterized in that, After making two parallel oblique cuts to the pipe, the obliquely cut pipe section is lifted off, the second pipe section is removed, and then the second pipe section is moved from the first position to the second position.

10. The method for parallel offsetting of a large-diameter pipeline according to claim 6, characterized in that, The number of the division points is even.

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