Measurement method for the elbow angle of PCCP pipe fittings

Abstract

The present application relates to a method for measuring a PCCP elbow, and particularly to a method for measuring the elbow angle of PCCP pipe fittings; it includes a left straight pipe, a left docking pipe, a right docking pipe and a right straight pipe; the inner diameters of the left straight pipe, the left docking pipe, the right docking pipe and the right straight pipe are all the same, and the outer diameters of the left straight pipe, the left docking pipe, the right docking pipe and the right straight pipe are all the same; the cross-section of the left docking pipe along the central plane is a right trapezoid. Due to the implementation of the above technical solution, in the present application, the ports of the left docking pipe corresponding to the oblique waist of the right trapezoid and the ports of the right docking pipe corresponding to the oblique waist of the right trapezoid are spot-welded together. By measuring the distance between specific punch marks, the elbow angle can be calculated, and the result is accurate. It can measure the actual manufacturing angle in advance during the welding and manufacturing process of the elbow, and can correct the manufacturing angle in a timely manner, avoiding large losses caused by difficulties in on-site installation or inability to install due to the inconsistency between the manufacturing angle and the design angle.

Description

Technical Field

[0001] This application relates to a method for measuring PCCP elbows, and particularly to a method for measuring the angles of PCCP pipe fittings elbows. Background Art

[0002] PCCP water conveyance pipelines have the advantages of multiple specifications, good adaptability, good sealing performance, long service life, earthquake resistance, convenient installation, and low maintenance costs, and are mainly used in fields such as long-distance and large-flow water conveyance and municipal water supply and drainage.

[0003] According to the characteristics of pipeline undulation and turning, steel pipe fittings with angles need to be configured at the inflection points. The accuracy requirements for the angles of pipe fittings during pipeline excavation and installation are relatively high (±0.5°), especially in rock sections or restricted areas, the accuracy requirements for the angles of pipe fittings are even higher (±0.2°).

[0004] When manufacturing steel pipe fittings with angles, processes such as lofting, cutting, rolling, assembling, and welding need to be carried out according to the angle requirements. Generally, when the angle is greater than 7°, it needs to be manufactured in sections. The larger the angle, the more sections there are, and the greater the cumulative error in manufacturing, which will cause the actual manufacturing angle of the steel pipe to deviate too much from the designed angle and not meet the requirements.

[0005] Therefore, after the pipe sections are assembled, the pipe fittings need to be spot-welded, temporarily fixed, and the angles need to be measured in advance. After meeting the designed angles, welding operations can be carried out. Otherwise, the angles need to be corrected before welding. The current measurement method is generally to measure and observe through a total station after the pipe joints are spot-welded, which takes a long time, requires a lot of effort, and has a high cost. Summary of the Invention

[0006] The purpose of this application is to propose a method for measuring the angles of pipe elbows and PCCP pipe fittings elbows that is fast, accurate, and low-cost.

[0007] One of the technical solutions of this application is realized as follows: A pipe elbow includes a left straight pipe, a left butt joint pipe, a right butt joint pipe, and a right straight pipe; the inner diameters of the left straight pipe, the left butt joint pipe, the right butt joint pipe, and the right straight pipe are all the same, and the outer diameters of the left straight pipe, the left butt joint pipe, the right butt joint pipe, and the right straight pipe are all the same; the cross-section of the left butt joint pipe along the central plane is a right trapezoid, and the port of the left butt joint pipe corresponding to the right-angled waist of the right trapezoid is fixedly connected to the left straight pipe through circumferential welding; the structure of the right butt joint pipe is symmetrical to the left butt joint pipe in the left-right direction, and the port of the left butt joint pipe corresponding to the inclined waist of the right trapezoid is spot-welded to the port of the right butt joint pipe corresponding to the inclined waist of the right trapezoid.

[0008] Further, at the position of the base angle of the oblique waist of the right-angled trapezoid, there are punch holes on the inner wall of the left docking pipe; at the position of the midpoint of the oblique waist of the right-angled trapezoid, there are punch holes on the inner wall of the left docking pipe; at the position of the apex angle of the oblique waist of the right-angled trapezoid, there are punch holes on the inner wall of the left docking pipe; at the position of the midpoint of the straight waist of the right-angled trapezoid, there are punch holes on both the front and rear inner walls of the left docking pipe; at the position of the apex angle of the straight waist of the right-angled trapezoid, there are punch holes on the inner wall of the left docking pipe; the punch hole positions on the inner wall of the right docking pipe are symmetrically distributed left and right with respect to the punch hole positions on the inner wall of the left docking pipe.

[0009] Further, the spot welding positions of the left docking pipe and the right docking pipe are both located at the punch hole positions.

[0010] Further, the left docking pipe is formed by rolling and welding a steel plate with a higher middle and lower ends, and the upper base of the right-angled trapezoid coincides with the longitudinal weld of the left docking pipe.

[0011] The second technical solution of this application is implemented as follows: A method for measuring the elbow angle of PCCP pipe fittings, which is characterized by including the following steps: First step, loft the steel plate made into the left docking pipe, divide the arc edge of the steel plate into four equal parts in length, and punch holes at five equal points: the first highest point, the first front middle point, the first rear middle point, the first front lowest point, and the first rear lowest point; divide the straight edge opposite to the arc edge of the steel plate into four equal parts in length, and punch holes at the middle three equal points: the third highest point, the third front middle point, and the third rear middle point; loft the steel plate made into the right docking pipe, divide the arc edge of the steel plate into four equal parts in length, and punch holes at five equal points: the second highest point, the second front middle point, the second rear middle point, the second front lowest point, and the second rear lowest point; divide the straight edge opposite to the arc edge of the steel plate into four equal parts in length, and punch holes at the middle three equal points: the fourth highest point, the fourth front middle point, and the fourth rear middle point; Second step, roll and longitudinally weld the two lofted steel plates respectively to make the left docking pipe and the right docking pipe with the same angle; align and spot-weld the punch holes at the first highest point, the first front middle point, the first rear middle point, the first front lowest point, and the first rear lowest point on the left docking pipe with the punch holes at the second highest point, the second front middle point, the second rear middle point, the second front lowest point, and the second rear lowest point on the right docking pipe respectively to form an angled steel cylinder; Third step, butt-joint and circumferentially weld the other port of the left docking pipe with the left straight pipe, and butt-joint and circumferentially weld the other port of the right docking pipe with the right straight pipe; Fourth step, determine the trapezoid position. The hexagon APBFQE obtained by the intersection of the inner wall of the angled steel cylinder formed in the second step and its central plane, the midpoint of side AE is point C, and the midpoint of side BF is point D, then ABCD is the isosceles trapezoid at the corner; The connection line between the third highest point and the fourth highest point coincides with AB, and the connection line between the third front middle point and the fourth front middle point is parallel and equidistant from CD; Fifth step, the waist AC of trapezoid ABCD is perpendicular to the axis of the left straight pipe, the waist BD of trapezoid ABCD is perpendicular to the axis of the right straight pipe, and the included angle between the extension lines of the waist AC and BD of trapezoid ABCD is the elbow angle a, DB = inner diameter of the steel pipe / 2, and line segment DG⊥AB; Sixth step, measure the length of line segment AB and the length of CD, and use the sine theorem to find ∠BDG = a / 2, that is: Sin(a / 2) = BG / BD = (length of AB - length of CD) / 2 / (inner diameter of the steel pipe / 2), and calculate to obtain the elbow angle a; Seventh step, compare the a obtained in the sixth step with the designed theoretical angle, and if the error range does not exceed ±0.2°, it is qualified.

[0012] By implementing the above technical solution, in the present application, the port of the left docking pipe corresponding to the inclined waist of the right-angled trapezoid is spot-welded to the port of the right docking pipe corresponding to the inclined waist of the right-angled trapezoid. By measuring a specific punching distance, the elbow angle can be calculated with high precision. This enables the actual manufacturing angle to be measured in advance during the elbow welding process and allows for timely correction of the manufacturing angle, thus avoiding significant losses caused by difficulties or impossibilities in on-site installation due to discrepancies between the manufacturing angle and the designed angle. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The specific structure of the present application is shown in the following drawings and embodiments:

[0014] Figure 1 are schematic diagrams of Embodiment 1 and Embodiment 2 of the present application;

[0015] Figure 2 is Figure 1 the developed view of the left docking pipe in (the inner wall of the left docking pipe facing forward).

[0016] Legend: 1. left straight pipe, 2. left docking pipe, 3. right docking pipe, 4. right straight pipe, 5. third highest point, 6. first highest point, 7. first front middle point, 8. first rear middle point, 9. first front lowest point, 10. first rear lowest point, 11. third front middle point, 12. third rear middle point, d. inner diameter of the steel pipe. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0017] The present application is not limited by the following embodiments, and specific implementation manners can be determined according to the technical solution of the present application and actual situations.

[0018] Embodiment 1, as shown in Figure 1 and 2 , the pipe elbow includes a left straight pipe 1, a left docking pipe 2, a right docking pipe 3, and a right straight pipe 4; the inner diameters of the left straight pipe 1, the left docking pipe 2, the right docking pipe 3, and the right straight pipe 4 are all the same, and the outer diameters of the left straight pipe 1, the left docking pipe 2, the right docking pipe 3, and the right straight pipe 4 are all the same; the cross-section of the left docking pipe 2 along the central plane is a right-angled trapezoid, and the port of the left docking pipe 2 corresponding to the right-angled waist of the right-angled trapezoid is fixedly connected to the left straight pipe 1 by circumferential seam welding; the structure of the right docking pipe 3 is symmetric to the left and right of the structure of the left docking pipe 2, and the port of the left docking pipe 2 corresponding to the inclined waist of the right-angled trapezoid is spot-welded to the port of the right docking pipe 3 corresponding to the inclined waist of the right-angled trapezoid.

[0019] The cross-section of the left docking pipe 2 along the central plane is a right trapezoid, which can ensure that the axes of the left straight pipe 1 and the left docking pipe 2 coincide; the structure of the right docking pipe 3 is left-right symmetric with that of the left docking pipe 2; it can ensure that the axes of the right straight pipe 3 and the right docking pipe 4 coincide; therefore, the included angle between the axis of the left docking pipe 2 and the axis of the right docking pipe 3 is the elbow angle to be measured. The spot welding connection between the left docking pipe 2 and the right docking pipe 3 can realize the advance prediction and effective control of the angle during the manufacturing process of the angled pipe fitting; avoid angle deviation and material loss.

[0020] As Figure 1 , 2 shown, at the position of the bottom angle of the oblique waist corresponding to the right trapezoid, there are punch marks on the inner wall of the left docking pipe 2; at the position of the midpoint of the oblique waist corresponding to the right trapezoid, there are punch marks on the inner wall of the left docking pipe 2; at the position of the top angle of the oblique waist corresponding to the right trapezoid, there are punch marks on the inner wall of the left docking pipe 2; at the midpoint position of the straight waist corresponding to the right trapezoid, there are punch marks on both the front and rear inner walls of the left docking pipe 2; at the position of the top angle of the straight waist corresponding to the right trapezoid, there are punch marks on the inner wall of the left docking pipe 2; the punch mark positions on the inner wall of the right docking pipe 3 are distributed in left-right symmetry with the punch mark positions on the inner wall of the left docking pipe 2.

[0021] The cross-section of the central plane of the left docking pipe 2 is a right trapezoid, and the cross-section of the central plane of the right docking pipe 3 is a right trapezoid; the included angle between the right-angled sides of the two right trapezoids is the required elbow angle. By measuring the distance from the punch mark at the midpoint position of the straight waist corresponding to the front inner wall of the left docking pipe 2 to the punch mark at the midpoint position of the straight waist corresponding to the front inner wall of the right docking pipe 3 (or the punch marks are both on the rear inner wall), and the distance from the punch mark at the top angle position of the straight waist corresponding to the left docking pipe 2 to the punch mark at the top angle position of the straight waist corresponding to the right docking pipe 3, the elbow angle can be calculated.

[0022] As Figure 1 , 2 shown, the spot welding positions of the left docking pipe 2 and the right docking pipe 3 are both located at the punch mark positions. In this way, there is no need to adjust the positions and angles of the left docking pipe 2 and the right docking pipe 3; a plane is determined by three or more groups of punch marks, so as to ensure that the left docking pipe 2 and the right docking pipe 3 can be accurately docked according to the design, and ensure that the angle after spot welding does not deviate.

[0023] As Figure 2 shown, the left docking pipe 2 is formed by rolling and welding a steel plate with a higher middle and lower ends, and the upper base of the right trapezoid coincides with the longitudinal weld of the left docking pipe 2. In this way, the left docking pipe 2 is a symmetric figure during lofting, which is convenient for processing and manufacturing.

[0024] Example 2, as Figure 1 , 2As shown in the figure, a method for measuring the elbow angle of a PCCP pipe fitting includes the following steps: First step, loft the steel plate made into the left docking pipe 2, divide the arc edge of the steel plate into four equal parts in length, and punch holes at five equal points: the first highest point 6, the first front middle point 7, the first rear middle point 8, the first front lowest point 9, and the first rear lowest point 10; divide the straight edge opposite to the arc edge of the steel plate into four equal parts in length, and punch holes at the three middle equal points: the third highest point 5, the third front middle point 11, and the third rear middle point 12; loft the steel plate made into the right docking pipe 3, divide the arc edge of the steel plate into four equal parts in length, and punch holes at five equal points: the second highest point, the second front middle point, the second rear middle point, the second front lowest point, and the second rear lowest point; divide the straight edge opposite to the arc edge of the steel plate into four equal parts in length, and punch holes at the three middle equal points: the fourth highest point, the fourth front middle point, and the fourth rear middle point; Second step, roll and longitudinally weld the two lofted steel plates respectively to make the left docking pipe 2 and the right docking pipe 3 with the same angle; correspondingly dock and spot weld the punch holes at the first highest point 6, the first front middle point 7, the first rear middle point 8, the first front lowest point 9, and the first rear lowest point on the left docking pipe 2 with the punch holes at the second highest point, the second front middle point, the second rear middle point, the second front lowest point, and the second rear lowest point on the right docking pipe 3 to form an angled steel cylinder; Third step, dock the other port of the left docking pipe 2 with the left straight pipe 1 and perform circumferential welding, and dock the other port of the right docking pipe 3 with the right straight pipe 4 and perform circumferential welding; Fourth step, determine the trapezoid position. The hexagon APBFQE obtained by the intersection of the inner wall of the angled steel cylinder formed in the second step and its central plane. The midpoint of side AE is point C, and the midpoint of side BF is point D. Then ABCD is the isosceles trapezoid at the corner; The connection line between the third highest point 5 and the fourth highest point coincides with AB, and the connection line between the third front middle point 11 and the fourth front middle point is parallel and equidistant from CD; Fifth step, the waist AC of the trapezoid ABCD is perpendicular to the axis of the left straight pipe 1, the waist BD of the trapezoid ABCD is perpendicular to the axis of the right straight pipe 4, and the included angle between the extension lines of the waist AC and BD of the trapezoid ABCD is the elbow angle a. DB = inner diameter of the steel pipe / 2, and the line segment DG⊥AB; Sixth step, measure the length of the line segment AB and the length of CD, and use the sine theorem to find ∠BDG = a / 2, that is: Sin(a / 2) = BG / BD = (length of AB - length of CD) / 2 / (inner diameter d of the steel pipe / 2), and calculate the elbow angle a; Seventh step, compare the a obtained in the sixth step with the designed theoretical angle. If the error range does not exceed ±0.2°, it is qualified.

[0025] The line connecting the third highest point 5 of the left docking pipe 2 and the third highest point 5 of the right docking pipe 3 is AB, and the operator can quickly measure the length of AB by punching holes inside the steel cylinder; the length of the line connecting the third front middle point 11 of the left docking pipe 2 and the third front middle point 11 of the right docking pipe 3 is the length of CD, and the operator can quickly measure the length of AB by punching holes inside the steel cylinder.

[0026] In this application, by punching holes and connecting lines, the trapezoidal position of the cross-section of the steel pipe fitting is determined, and the turning angle is obtained by length measurement and inner diameter dimension.

[0027] Adopting this measurement method can accurately measure. When the measured angle does not match the designed angle, it can be discovered and corrected in time, realizing the advance prediction and effective control of the angle during the manufacturing process of the angled pipe fitting; ensuring that it matches the excavation angle of the pipe trench and meeting the installation requirements.

[0028] This application has been applied in the manufacturing of steel pipe fittings for the water conveyance pipeline project of some major water conservancy projects, and the effect is good. At the same time, it is applicable to the measurement of angled elbows made of other materials, with a wide range of applications, and can be further promoted and applied.

[0029] In this article, "up", "down", "front", "back", "left", "right", etc. are only used to represent the relative positional relationship between relevant parts, rather than limiting the absolute positions of these relevant parts.

[0030] The above technical features constitute the embodiments of this application, which have strong adaptability and implementation effects. Non-essential technical features can be added or subtracted according to actual needs to meet the needs of different situations.

Claims

1. A method for measuring the elbow angle of PCCP pipe fittings, characterized in that it includes a pipe elbow, which consists of a left straight pipe, a left docking pipe, a right docking pipe and a right straight pipe; the inner diameters of the left straight pipe, the left docking pipe, the right docking pipe and the right straight pipe are all the same, and the outer diameters of the left straight pipe, the left docking pipe, the right docking pipe and the right straight pipe are all the same; the cross-section of the left docking pipe along the central plane is a right trapezoid, and the port of the left docking pipe corresponding to the right-angled waist of the right trapezoid is fixedly connected to the left straight pipe by circumferential seam welding; the structure of the right docking pipe is symmetrical to that of the left docking pipe left and right, and the port of the left docking pipe corresponding to the inclined waist of the right trapezoid is spot-welded to the port of the right docking pipe corresponding to the inclined waist; at the position corresponding to the bottom angle of the inclined waist of the right trapezoid, there are punch marks on the inner wall of the left docking pipe; at the position corresponding to the midpoint of the inclined waist of the right trapezoid, there are punch marks on the inner wall of the left docking pipe; at the position corresponding to the top angle of the inclined waist of the right trapezoid, there are punch marks on the inner wall of the left docking pipe; at the midpoint position of the straight waist of the right trapezoid, there are punch marks on the front and rear inner walls of the left docking pipe; at the position corresponding to the top angle of the straight waist of the right trapezoid, there are punch marks on the inner wall of the left docking pipe; the punch mark positions on the inner wall of the right docking pipe are symmetrically distributed left and right with respect to the punch mark positions on the inner wall of the left docking pipe; Measurement includes the following steps: The first step is to loft the steel plate made into the left docking pipe, divide the arc edge of the steel plate into four equal parts in length, and punch holes at the five equal points: the first highest point, the first front middle point, the first rear middle point, the first front lowest point, and the first rear lowest point; divide the straight edge opposite to the arc edge of the steel plate into four equal parts in length, and punch holes at the three middle equal points: the third highest point, the third front middle point, and the third rear middle point; loft the steel plate made into the right docking pipe, divide the arc edge of the steel plate into four equal parts in length, and punch holes at the five equal points: the second highest point, the second front middle point, the second rear middle point, the second front lowest point, and the second rear lowest point; divide the straight edge opposite to the arc edge of the steel plate into four equal parts in length, and punch holes at the three middle equal points: the fourth highest point, the fourth front middle point, and the fourth rear middle point; The second step is to roll and longitudinally weld the two lofted steel plates respectively to make the left docking pipe and the right docking pipe with the same angle; the punch holes at the first highest point, the first front middle point, the first rear middle point, the first front lowest point, and the first rear lowest point on the left docking pipe are respectively butted and spot-welded with the punch holes at the second highest point, the second front middle point, the second rear middle point, the second front lowest point, and the second rear lowest point on the right docking pipe to form an angled steel cylinder; The third step is to dock the other port of the left docking pipe with the left straight pipe and perform circumferential seam welding, and dock the other port of the right docking pipe with the right straight pipe and perform circumferential seam welding; The fourth step is to determine the trapezoid position. The hexagon APBFQE obtained by intercepting the inner wall of the angled steel cylinder formed in the second step with its central plane, the midpoint of side AE is point C, and the midpoint of side BF is point D, then ABCD is the isosceles trapezoid at the corner; the line connecting the third highest point and the fourth highest point coincides with AB, and the line connecting the third front middle point and the fourth front middle point is parallel and equidistant from CD; Step 5: The waist AC of trapezoid ABCD is perpendicular to the axis of the left straight pipe, and the waist BD of trapezoid ABCD is perpendicular to the axis of the right straight pipe. The included angle between the extended lines of the waists AC and BD of trapezoid ABCD is the elbow angle a. DB = inner diameter of the steel pipe / 2, and the line segment DG ⊥ AB; Step 6: Measure the lengths of line segments AB and CD, and use the sine theorem to find ∠BDG = a / 2, that is: Sin(a / 2) = BG / BD = (length of AB - length of CD) / 2 / (inner diameter of the steel pipe / 2), and calculate the elbow angle a; Step 7: Compare the a obtained in Step 6 with the designed theoretical angle. If the error range does not exceed ±0.2°, it is qualified.

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