Horizontal measuring and adjusting method for low-pressure outer cylinder of three-valve structure of steam turbine

Abstract

The invention discloses a steam turbine three-valve structure low-pressure outer cylinder horizontal measurement and adjustment method, and belongs to the technical field of steam turbine precise assembly. The method solves the technical problem of low installation efficiency caused by high accumulative error value of a multi-petal structure, high planeness out-of-tolerance value and insufficient dynamic coordination in the existing horizontal adjustment process for the low-pressure outer cylinder of the three-petal structure of the steam turbine. Measurement and adjustment methods of preliminary adjustment, linkage alignment, flatness modeling and flatness correction are adopted, and flatness modeling comprises the step of arranging n measuring points in the perimeter direction of the lower half of an outer cylinder; measuring the horizontal value Nn between the adjacent measuring points through a gradienter, and measuring the distance Sn between the adjacent measuring points through a range finder; calculating a horizontal contribution value Ln = Nn * Sn between adjacent measuring points of each section; calculating a height value Hn of each measuring point by accumulating Ln, and selecting a highest value Hmax and a lowest value Hmin from a plurality of Hn; and judging whether a design value is met, and outputting a result. And the measurement and adjustment accuracy is improved. The method is used for assembling the steam turbine outer cylinder.

Description

Technical Field

[0001] The invention relates to a method for measuring and adjusting the level of a low-pressure outer cylinder of a three-petal structure of a steam turbine, and belongs to the technical field of precise assembly of steam turbines. Background Art

[0002] The horizontal adjustment process of the low-pressure outer cylinder of the traditional three-petal structure of the steam turbine has the following technical defects: First, the benchmark is not unified: there is a lack of coordinated control when adjusting the outer cylinders at the adjustment end, middle part, and electric end separately, which easily leads to cumulative errors in the height difference of the center dividing surface; second, the measurement efficiency is low: the horizontal adjustment relies on multiple trial installations and manual experience judgment, and the time consumed by repeated measurements accounts for more than 75% of the overall construction period; third, the flatness control is insufficient: the traditional shim arrangement has not established a mathematical model, and the distortion of the horizontal surface of the entire cylinder cannot be quantified, and the flatness qualification rate is extremely low; fourth, the dynamic coordination is poor: the center alignment of the expansion joint cavity and the inner cylinder support is not coordinated and adjusted.

[0003] The existing horizontal adjustment process of the low-pressure outer cylinder of the three-petal structure of the steam turbine has technical problems such as high cumulative error value of the multi-petal structure, high flatness deviation value and insufficient dynamic coordination, which in turn leads to low installation efficiency. Summary of the Invention

[0004] The present invention solves the technical problems of the existing steam turbine three-petal structure low-pressure outer cylinder horizontal adjustment process, such as high multi-petal structure cumulative error, high flatness deviation, and insufficient dynamic coordination, which leads to low installation efficiency. A method for measuring and adjusting the level of a steam turbine three-petal structure low-pressure outer cylinder is provided, which comprises the following steps: S1. Perform preliminary split adjustments on the lower half of the three-petal low-pressure outer casing of the steam turbine through the base frame; S2. Use the dummy shaft support to perform linkage alignment on the lower half of the three-petal low-pressure outer cylinder of the steam turbine; S3. Performing flatness modeling on the lower half of the three-petal low-pressure outer casing of the steam turbine; the modeling includes the following steps: S3-1. Arrange n measuring points along the circumference of the lower half of the low-pressure outer casing of the three-petal structure of the steam turbine; S3-2, using a level meter to measure the level value Nn between adjacent measuring points, and using a distance meter to measure the distance Sn between adjacent measuring points; S3-3. Calculate the horizontal contribution value Ln=Nn*Sn between each adjacent measuring point; S3-4, calculate the height value Hn of each measuring point by accumulating Ln, and select the highest value Hn from several Hn max and the lowest value H min ; S3-5. Determine the highest value H max and the lowest value H min Check whether the height difference meets the design value and output the result; S4. Correct the flatness of the lower half of the three-petal low-pressure outer casing of the steam turbine using the output results of the modeling.

[0005] As another improvement of the present invention, step S1 includes the following steps: S1-1. Hoist the lower half of the three-petal low-pressure outer cylinder of the steam turbine, including the power-end outer cylinder, the regulating-end outer cylinder, and the middle outer cylinder, to the base frame. Use feeler gauges to check the contact surface clearances between the power-end outer cylinder, the regulating-end outer cylinder, and the middle outer cylinder and the base frame. S1-2. Adjust the contact surface gaps between the electric end outer cylinder, the adjustment end outer cylinder, the middle outer cylinder and the base frame respectively, so that the contact surface gaps are all less than 0.05mm; S1-3. Use a straightedge and a level to measure the horizontal value of the center dividing surface of the outer cylinder at the end of the adjustment. Use the hydraulic jack at the bottom of the base frame to adjust the horizontal value of the center dividing surface of the outer cylinder at the end of the adjustment to a deviation of no more than 0.05 mm / m. S1-4, adjust the height of the center dividing surface of the middle outer cylinder so that the difference between the center dividing surface height of the middle outer cylinder and the center dividing surface height of the adjustment end outer cylinder is within the range of -0.05mm to +0.05mm. S1-5. Adjust the horizontal value of the electric end outer cylinder to no more than 0.05mm / m, and adjust the height of the center dividing surface of the electric end outer cylinder so that the difference between the height of the center dividing surface of the electric end outer cylinder and the height of the center dividing surface of the middle outer cylinder is in the range of -0.05mm to +0.05mm.

[0006] As another improvement of the present invention, step S2 includes the following steps: S2-1. Arrange dummy shaft supports on the outer sides of the power-end outer cylinder and the regulating-end outer cylinder of the lower half of the three-petal low-pressure outer cylinder of the steam turbine; S2-2. Adjust the concentricity of the electric end outer cylinder, the regulating end outer cylinder and the middle outer cylinder of the lower half of the three-petal structure low-pressure outer cylinder of the steam turbine through the dummy shaft bracket. The concentricity of the electric end outer cylinder, the regulating end outer cylinder and the middle outer cylinder with the dummy shaft shall not exceed 0.03mm.

[0007] As another improvement of the present invention, it also comprises the following steps: S5. Pre-tighten the bolts on the center plane of the three-valve low-pressure outer casing of the steam turbine. The number of pre-tightened bolts is 1 / 3 of the total number of bolts. Re-measure the clearance on the center plane. S6. Install the positioning bolts, check the deflection of the pin holes of the positioning bolts, and mark the pin holes that have passed the inspection.

[0008] As another improvement of the present invention, step S5 is specifically: use a hydraulic tensioner to pre-tighten the bolts perpendicular to the center dividing surface, the pre-tightened number is 1 / 3 of the total number of bolts, the pre-tightened bolts are evenly arranged, and the gap value between the center dividing surface and the base frame is re-measured. The qualified value range of the gap value between the center dividing surface and the base frame is not more than 0.05mm.

[0009] As another improvement of the present invention, in step S6, the deflection of the pin hole of the positioning bolt is detected, and the qualified value range of the deflection of the pin hole is not greater than 0.02 mm.

[0010] As another improvement of the present invention, in step S3-1, 16 measuring points are arranged along the circumference of the lower half of the low-pressure outer casing of the three-petal structure of the steam turbine.

[0011] As another improvement of the present invention, the distance between adjacent measuring points in step S3-1 is no more than 1.5 m. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a schematic diagram of the flatness modeling of the lower half of the low-pressure outer casing of the three-petal structure of the steam turbine.

[0013] Figure 2 It is a schematic diagram of the lower half of the low-pressure outer cylinder of the three-petal structure of the steam turbine. DETAILED DESCRIPTION

[0014] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the examples of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all embodiments obtained by ordinary technicians in this field without making any creative work shall fall within the scope of protection of the present invention.

[0015] Specific implementation method 1: Combination Figure 1 and Figure 2 This embodiment describes a method for measuring and adjusting the level of a low-pressure outer cylinder of a three-petal structure of a steam turbine, which includes the following steps: S1. Perform preliminary split adjustments on the lower half of the three-petal low-pressure outer casing of the steam turbine through the base frame; S2. Use the dummy shaft support to perform linkage alignment on the lower half of the three-petal low-pressure outer cylinder of the steam turbine; S3. Performing flatness modeling on the lower half of the three-petal low-pressure outer casing of the steam turbine; the modeling includes the following steps: S3-1. Arrange n measuring points along the circumference of the lower half of the three-lobe low-pressure outer casing of the steam turbine. Place shims at the measuring points, and the heights of the shims are equal. S3-2, using a level meter to measure the level value Nn between adjacent measuring points, and using a distance meter to measure the distance Sn between adjacent measuring points; S3-3. Calculate the horizontal contribution value Ln=Nn*Sn between each adjacent measuring point; S3-4, calculate the height value Hn of each measuring point by accumulating Ln, and select the highest value Hn from several Hn max and the lowest value Hmin ; Based on the adjustment end, define the positive direction of the horizontal high position, calculate the cumulative value of each point, and determine the highest point H of the entire cylinder max With the lowest point H min ; S3-5. Determine the highest value H max and the lowest value H min Check whether the height difference meets the design value and output the result; S4. Correct the flatness of the lower half of the low-pressure outer cylinder of the three-petal structure of the steam turbine through the output results of the modeling. The flatness of the entire cylinder is H = |H max | + |H min If H is greater than the design value, the base frame jack will be used for dynamic adjustment, raising the low point and lowering the high point until H is fully Sufficient design value .

[0016] This method achieves efficient and precise assembly of the low-pressure outer cylinder through phased coordinated adjustment, dummy-axis-assisted alignment, and quantitative control of full-cylinder flatness. It focuses on addressing cumulative errors, flatness tolerances, and dynamic coordination issues in the three-petal structure, ensuring the fit of the horizontal center plane and cylinder coaxiality. This reduces the risks of post-assembly clearance tolerances and flatness errors, and improves the first-pass pass rate for installation.

[0017] Applying this method significantly shortens the time required to horizontally adjust the low-pressure outer cylinder and significantly improves the flatness qualification rate. By modeling the flatness of the lower half of the three-lobe low-pressure outer cylinder of a steam turbine, low points can be quickly identified and precisely adjusted, ensuring accurate outer cylinder flatness measurement and reducing the likelihood of unqualified cylinder centerline clearances due to flatness errors later in the process.

[0018] Specific implementation method 2: Combination Figure 1 and Figure 2 This embodiment is described. The difference between this embodiment and the first embodiment is that step S1 includes the following steps: S1-1. Hoist the lower half of the three-petal low-pressure outer cylinder of the steam turbine, including the power-end outer cylinder, the regulating-end outer cylinder, and the middle outer cylinder, to the base frame. Use feeler gauges to check the contact surface clearances between the power-end outer cylinder, the regulating-end outer cylinder, and the middle outer cylinder and the base frame. S1-2. Adjust the contact surface gaps between the electric end outer cylinder, the adjustment end outer cylinder, the middle outer cylinder and the base frame respectively, so that the contact surface gaps are all less than 0.05mm; S1-3. Use a straightedge and a level to measure the horizontal value of the center dividing surface of the outer cylinder at the end of the adjustment. Use the hydraulic jack at the bottom of the base frame to adjust the horizontal value of the center dividing surface of the outer cylinder at the end of the adjustment to a deviation of no more than 0.05 mm / m. S1-4, adjust the height of the center dividing surface of the middle outer cylinder so that the difference between the center dividing surface height of the middle outer cylinder and the center dividing surface height of the adjustment end outer cylinder is within the range of -0.05mm to +0.05mm. S1-5. Adjust the horizontal value of the electric end outer cylinder to no more than 0.05mm / m. Adjust the height of the center plane of the electric end outer cylinder so that the difference between the center plane of the electric end outer cylinder and the center plane of the middle outer cylinder is within the range of -0.05mm to +0.05mm. This design is designed to enhance the accuracy of the initial adjustment.

[0019] Specific implementation method three: Combination Figure 1 and Figure 2 This embodiment is described. The difference between this embodiment and the first embodiment is that step S2 includes the following sub-steps: S2-1. Arrange dummy shaft supports on the outer sides of the power-end outer cylinder and the regulating-end outer cylinder of the lower half of the three-petal low-pressure outer cylinder of the steam turbine; S2-2. Using a dummy shaft support, adjust the concentricity of the power-end, adjustment-end, and center outer cylinders in the lower half of the turbine's three-lobed low-pressure outer cylinder. The concentricity of the power-end, adjustment-end, and center outer cylinders with the dummy shaft should be no greater than 0.03mm. The expansion joint dimples and the inner cylinder supports are adjusted in a coordinated manner. Each measurement simultaneously aligns the power-end, adjustment-end, and center outer cylinders. This design enhances alignment accuracy.

[0020] Specific implementation method four: Combination Figure 1 and Figure 2 This embodiment is described. The difference between this embodiment and the first embodiment is that this embodiment further includes the following steps: S5. Pre-tighten the bolts on the center plane of the three-valve low-pressure outer casing of the steam turbine. The number of pre-tightened bolts is 1 / 3 of the total number of bolts. Re-measure the clearance on the center plane. S6. Install the positioning bolts, check the deflection of the positioning bolt pin holes, and mark the pin holes that pass the test. The positioning bolts are eccentric bushing positioning bolts.

[0021] Specific implementation method five: Combination Figure 1 and Figure 2 To explain this embodiment, the difference between this embodiment and the specific embodiment 1 is that step S5 is specifically: use a hydraulic tensioner to pre-tighten the bolts perpendicular to the center dividing surface, the pre-tightened number is 1 / 3 of the total number of bolts, tighten one every two bolts, the pre-tightened bolts are evenly arranged, and the gap value between the center dividing surface and the base frame is re-measured. The qualified value range of the gap value between the center dividing surface and the base frame is not more than 0.05mm.

[0022] Specific implementation method six: combination Figure 1 and Figure 2 This embodiment is described. The difference between this embodiment and the first embodiment is that the pin hole deflection of the positioning bolt is detected in step S6. The qualified value range of the pin hole deflection is not greater than 0.02 mm.

[0023] Specific implementation method seven: combination Figure 1 and Figure 2 This embodiment is described. The difference between this embodiment and the first embodiment is that in step S3-1, 16 measuring points are arranged along the circumference of the lower half of the three-petal low-pressure outer casing of the steam turbine.

[0024] Specific implementation method eight: combination Figure 1 and Figure 2 This embodiment is described. The difference between this embodiment and the first embodiment is that the distance between adjacent measuring points in step S3-1 is no more than 1.5 m. This design is intended to enhance measurement accuracy.

[0025] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for measuring and adjusting the level of a low-pressure outer cylinder of a three-petal structure of a steam turbine, characterized in that It includes the following steps: S1. Perform preliminary split adjustments on the lower half of the three-petal low-pressure outer casing of the steam turbine through the base frame; S2. Use the dummy shaft support to perform linkage alignment on the lower half of the three-petal low-pressure outer cylinder of the steam turbine; S3. Performing flatness modeling on the lower half of the three-petal low-pressure outer casing of the steam turbine; the modeling includes the following steps: S3-1. Arrange n measuring points along the circumference of the lower half of the low-pressure outer casing of the three-petal structure of the steam turbine; S3-2, using a level meter to measure the level value Nn between adjacent measuring points, and using a distance meter to measure the distance Sn between adjacent measuring points; S3-3. Calculate the horizontal contribution value Ln=Nn*Sn between each adjacent measuring point; S3-4, calculate the height value Hn of each measuring point by accumulating Ln, and select the highest value Hn from several Hn max and the lowest value H min ; S3-5. Determine the highest value H max and the lowest value H min Check whether the height difference meets the design value and output the result; S4. Correct the flatness of the lower half of the low-pressure outer casing of the three-petal structure of the steam turbine based on the output results of the modeling.

2. A method for measuring and adjusting the level of a three-petal structure low-pressure outer cylinder of a steam turbine according to claim 1, characterized in that: Step S1 includes the following steps: S1-1. Hoist the lower half of the three-petal low-pressure outer cylinder of the steam turbine, including the power-end outer cylinder, the regulating-end outer cylinder, and the middle outer cylinder, to the base frame. Use feeler gauges to check the contact surface clearances between the power-end outer cylinder, the regulating-end outer cylinder, and the middle outer cylinder and the base frame. S1-2. Adjust the contact surface gaps between the electric end outer cylinder, the adjustment end outer cylinder, the middle outer cylinder and the base frame respectively, so that the contact surface gaps are all less than 0.05mm; S1-3. Use a straightedge and a level to measure the horizontal value of the center dividing surface of the outer cylinder at the end of the adjustment. Use the hydraulic jack at the bottom of the base frame to adjust the horizontal value of the center dividing surface of the outer cylinder at the end of the adjustment to a deviation of no more than 0.05 mm / m. S1-4, adjust the height of the center dividing surface of the middle outer cylinder so that the difference between the center dividing surface height of the middle outer cylinder and the center dividing surface height of the adjustment end outer cylinder is within the range of -0.05mm to +0.05mm. S1-5. Adjust the horizontal value of the electric end outer cylinder to no more than 0.05mm / m, and adjust the height of the center dividing surface of the electric end outer cylinder so that the difference between the height of the center dividing surface of the electric end outer cylinder and the height of the center dividing surface of the middle outer cylinder is in the range of -0.05mm to +0.05mm.

3. The method for measuring and adjusting the level of a three-petal structure low-pressure outer cylinder of a steam turbine according to claim 1, characterized in that: Step S2 includes the following steps: S2-1. Arrange dummy shaft supports on the outer sides of the power-end outer cylinder and the regulating-end outer cylinder of the lower half of the three-petal low-pressure outer cylinder of the steam turbine; S2-2. Adjust the concentricity of the electric end outer cylinder, the regulating end outer cylinder and the middle outer cylinder of the lower half of the three-petal structure low-pressure outer cylinder of the steam turbine through the dummy shaft bracket. The concentricity of the electric end outer cylinder, the regulating end outer cylinder and the middle outer cylinder with the dummy shaft shall not exceed 0.03mm.

4. A method for measuring and adjusting the level of a three-petal structure low-pressure outer cylinder of a steam turbine according to claim 1, characterized in that It also includes the following steps: S5. Pre-tighten the bolts on the center plane of the three-valve low-pressure outer casing of the steam turbine. The number of pre-tightened bolts is 1 / 3 of the total number of bolts. Re-measure the clearance on the center plane. S6. Install the positioning bolts, check the deflection of the pin holes of the positioning bolts, and mark the pin holes that have passed the inspection.

5. A method for measuring and adjusting the level of a three-petal structure low-pressure outer cylinder of a steam turbine according to claim 4, characterized in that: Step S5 is specifically as follows: use a hydraulic tensioner to pre-tighten the bolts perpendicular to the center dividing surface, the pre-tightened number is 1 / 3 of the total number of bolts, the pre-tightened bolts are evenly arranged, and the gap value between the center dividing surface and the base frame is re-measured. The qualified value range of the gap value between the center dividing surface and the base frame is not more than 0.05mm.

6. A method for measuring and adjusting the level of a three-petal structure low-pressure outer cylinder of a steam turbine according to claim 4, characterized in that: In step S6, the pin hole deflection of the positioning bolt is detected, and the qualified value range of the pin hole deflection is not greater than 0.02 mm.

7. The method for measuring and adjusting the level of a three-petal structure low-pressure outer cylinder of a steam turbine according to claim 1, characterized in that: In step S3-1, 16 measuring points are arranged along the circumference of the lower half of the three-lobed low-pressure outer casing of the steam turbine.

8. The method for measuring and adjusting the level of a three-petal structure low-pressure outer cylinder of a steam turbine according to claim 1, characterized in that: The distance between adjacent measuring points in step S3-1 is no greater than 1.5 m.

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