A Construction Center Positioning Device for the Stator Pit of a Generator and Its Positioning Detection Method

Abstract

The present invention discloses a construction center positioning device for a generator stator pit and a positioning detection method thereof. The positioning device includes a dummy shaft device arranged at the center of the pit bottom. The dummy shaft device includes a dummy shaft center column capable of adjusting the verticality and horizontal center position in a horizontal state. The dummy shaft center column and the center column of the circle measuring frame are located on the same vertical line at the center of the generator stator pit; the detection method includes the concentricity verification and positioning between the dummy shaft device and the bottom ring water stop ring, and the concentricity verification and positioning between the dummy shaft device and the stator circle measuring frame. In the present invention, a dummy shaft device is installed at the position of the bottom ring water stop ring, and the center of the stator circle measuring frame is directly detected by using this device with the center of the bottom ring water stop ring of the turbine component as the reference, without re-erecting a centering beam and hanging a piano wire; by adjusting the center adjustment bolt of the dummy shaft device, the center column of the dummy shaft device is adjusted to be concentric with the bottom ring water stop ring, or the circle measuring frame is moved so that the center of the circle measuring frame is located on the unit center; the construction time is reduced and the installation accuracy is improved.

Description

Technical Field

[0001] The invention relates to the technical field of electromechanical equipment installation of hydropower stations, and in particular to a detection device and a positioning detection method for measuring the concentricity of a circular frame center with a pit center when a hydro-generator stator is assembled in a pit. Background Art

[0002] The stators of the generators of large hydropower stations arrive as spare parts and are assembled into a whole through a series of processes on site. During the assembly process, the radius and center of the stator are measured and controlled using a stator circle measuring frame and an inside micrometer installed in the center. Therefore, how to detect whether the center of the circle measuring frame is in the center of the pit (that is, whether the center column of the circle measuring frame is concentric with the pit) and whether the center of the circle measuring frame is displaced is the key to controlling the quality of stator assembly. For stator assembly in the pit, after the circle measuring frame is installed, the center measurement reference of the unit (the center of the bottom ring stop ring) has been completely blocked by the stator assembly platform, and the center of the bottom ring stop ring cannot be directly used as a reference to check whether the center of the circle measuring frame is located on the center of the unit. It is usually used to reverse the center monitoring reference point on the stator base to assist in the verification and adjustment of the center of the circle measuring frame, which is implemented through the following schemes:

[0003] 1) After the base of the split stator is hoisted into the pit group, the assembly platform and the circular frame foundation in the stator pit are hoisted in turn, and the centring beam (including the center alignment device - the centring device) is hoisted to the top of the stator on the generator layer of the pit. The piano wire is suspended to the position below the bottom ring of the turbine. The center of the bottom ring leak-proof ring (the center measurement reference of the unit) is used as the reference, and the "electrical measurement method" is used to measure the distance from the measuring point in the X and Y axis directions to the piano wire. According to the measurement data, the centring device is moved so that the piano wire is located at the center of the unit. With the piano wire as the reference, the distance from the measuring point corresponding to the X and Y axis of the lower ring plate of the stator base to the piano wire is measured. According to the measurement data, the stator base is moved so that the center of the stator base and the center of the unit are on the same straight line, and then the stator base is fixed.

[0004] 2) Remove the centring beam, install the stator circle measuring frame, and use the four measuring points corresponding to the X and Y axis directions when the center of the stator base is adjusted as the reference to measure the distance to the center column of the circle measuring frame. According to the measurement data, move the stator circle measuring frame so that the center of the circle measuring frame is located at the center of the stator, that is, at the center of the unit, and then adjust the verticality of the circle measuring frame to meet the requirements. Re-measure the center of the circle measuring frame and it should meet the requirements.

[0005] 3) Taking the center column of the stator circle measuring frame as the reference, weld a circle measuring frame center detection fixing block at the position of the X and Y axis directions on the stator base that does not affect the stator assembly, and make a center monitoring reference point at its center position, measure the initial distance from the center monitoring reference point to the center column of the circle measuring frame, and record it. During the assembly process, directly measure the distance from the center monitoring reference point to the center column of the circle measuring frame, compare it with the initial value, judge the displacement of the center of the circle measuring frame, and make adjustments based on the measurement data.

[0006] The problems existing in this solution are as follows: The detection of the center of the stator circle measuring frame is not real and accurate enough. Since the center monitoring reference point is determined through reverse setting two or more times, there is a large measurement error in the center reverse point. Compared with the calibration method directly based on the center of the bottom ring seal ring, the deviation can reach 0.20 mm or more, while the allowable value of the stator installation center deviation in the installation process specification of the manufacturer is 0.25 mm, and the data is relatively close. Therefore, after the stator is assembled in the pit, in order to reduce the deviation between the stator center and the unit center, the centering beam is often erected again and the piano wire is hung after removing the circle measuring frame and the stator assembly construction platform. Based on the center of the bottom ring seal ring, the stator center is measured again. If there is a large deviation, the stator center needs to be adjusted twice. In addition, in actual construction, affected by factors such as vibration and the gradually increasing weight of the stator, the stator circle measuring frame and the stator will have different degrees of displacement, and the measured data cannot directly determine whether it is the stator displacement or the circle measuring frame displacement. Therefore, after the circle measuring frame or the stator is adjusted, the stator center deviation value will increase, and in severe cases, it will also cause secondary adjustment of the stator in the pit after assembly. Due to the relatively poor overall stiffness of the stator, local extrusion deformation (this deformation includes plastic deformation and elastic deformation) will occur under the action of external forces, and part of it will rebound after the external force is removed (the elastic deformation will rebound), resulting in repeated adjustment, which in turn affects the accuracy of the stator center adjustment. Summary of the Invention

[0007] The present invention discloses a center positioning device and its positioning detection method for the construction of a generator stator pit according to the deficiencies of the prior art. The problem to be solved by the present invention is to provide a center detection device and its positioning detection method for the circle measuring frame used in the assembly of a hydrogenerator stator in the pit, which are convenient to operate and have accurate measurement data.

[0008] The present invention is realized through the following technical solutions:

[0009] First, the present invention discloses a center positioning device for the construction of a generator stator pit.

[0010] For the center positioning device of the generator stator pit construction, a bottom ring seal ring is provided at the bottom of the engine stator pit, and a stator circle measuring frame is provided above the pit. The stator circle measuring frame includes a circle measuring frame center column. It is characterized in that: a false shaft device is provided at the center of the bottom of the pit. The false shaft device includes a false shaft center column that can adjust the verticality and horizontal center position of the horizontal state. The false shaft center column and the circle measuring frame center column are located on the same vertical line at the center of the engine stator pit.

[0011] Furthermore, the dummy shaft device includes: a dummy shaft central column, a base and a fixing seat for fixing the dummy shaft central column, a shaft holding device and shaft holding adjustment bolts for adjusting the perpendicularity of the dummy shaft. The base and the fixing seat are welded into an integral body and fixed on the foundation seat. The base adjusts its horizontal state through horizontal adjustment bolts, adjusts its central position through at least two groups of gravity center adjustment bolts and adjustment brackets, and is fixed through fastening bolts.

[0012] Each group of gravity center adjustment bolts and adjustment brackets are arranged on the foundation seat and symmetrically arranged along the circumference of the base; the adjustment brackets are welded and fixed on the foundation seat, and the top ends of the gravity center adjustment bolts are in contact with the circumferential wall of the base for adjustment.

[0013] The fastening bolts are arranged on one side of the base to connect and fix the base to the foundation seat, and horizontal adjustment bolts with their tops in contact with the surface of the foundation seat are arranged on the plane of the base symmetrical to the fastening bolts.

[0014] The foundation seat is fixed on the structural body at the bottom of the pit.

[0015] The method for positioning the stator circle measuring frame of the generator stator by the above positioning device of the present invention includes the following steps:

[0016] 1) Checking and positioning the concentricity between the dummy shaft device and the bottom ring water stop ring:

[0017] ① The dummy shaft device is arranged on the central foundation ring at the bottom of the pit, and the dummy shaft central column of the dummy shaft device is at the same elevation as the bottom ring water stop ring;

[0018] ② Use a frame level to measure the perpendicularity in the four directions of the X-axis and Y-axis of the dummy shaft central column, and roughly adjust the perpendicularity of the dummy shaft central column ≤ 0.02 mm / m;

[0019] ③ Use an internal diameter micrometer to measure the distances E and F between the dummy shaft central column through the upper ring and the lower ring of the bottom ring water stop ring:

[0020] On the same ring surface, check that the central deviation of the two corresponding measuring points in the X direction ≤ 0.05 mm, the central deviation of the two corresponding measuring points in the Y direction ≤ 0.05 mm, and the combined central deviation value in the X and Y directions is also ≤ 0.05 mm, which indicates that the dummy shaft central column is located on the unit center; if the requirements are not met, move the dummy shaft device to adjust the dummy shaft central column so that its center is located on the unit center;

[0021] On the same vertical surface, check the two corresponding measuring points in the X direction and the difference between their corresponding E and F values, and precisely adjust the perpendicularity of the dummy shaft central column, with its deviation ≤ 0.02 mm, which indicates that the dummy shaft central column is vertical; if the requirements are not met, adjust the horizontal adjustment bolts of the dummy shaft device to adjust the dummy shaft central column to make it vertical;

[0022] 2) Checking and positioning the concentricity between the dummy shaft device and the stator circle measuring frame:

[0023] ④ Four piano wires are erected along the four measuring point directions of the X-axis and Y-axis on the outside of the stator central column. The lower ends of the piano wires are connected to plumb bobs, and the plumb bobs are placed in an oil barrel.

[0024] ⑤ Measure the distances A, B, C, and D from the stator central column and the dummy shaft central column to the piano wires at each measuring point respectively. Using the electrical measurement method, measure the concentricity of the stator central column and the dummy shaft central column through the external measurement method of coaxiality:

[0025] On the same vertical plane, check the two corresponding measuring points in the X direction and the difference between the corresponding A and B. Adjust the verticality of the stator central column. If the deviation is ≤ 0.02 mm, it indicates that the central column of the stator circle measuring frame is vertical; if the requirement is not met, it is necessary to adjust the horizontal adjustment bolts of the stator circle measuring frame to make it vertical.

[0026] On the same toroidal plane, check the relative deviation values of the corresponding points of A, B, C, and D at the two measuring points in the X direction, calculate the central deviation value ≤ 0.05 mm, and check the relative deviation values of the corresponding points of A, B, C, and D at the two measuring points in the Y direction, calculate the central deviation ≤ 0.05 mm, which indicates that the stator central column is located on the unit center; if the requirement is not met, it is necessary to adjust the stator circle measuring frame so that the center of the stator central column is located on the unit center.

[0027] Compared with the prior art, the beneficial effects of the present invention are:

[0028] 1. The present invention installs a dummy shaft device at the position of the bottom ring seal ring. During the assembly of the stator in the pit, the center of the stator circle measuring frame is directly detected through this device with the center of the bottom ring seal ring of the turbine component as the reference, ensuring that the stator is installed in place at one time.

[0029] 2. During the measurement process, there is no need to install the centering beam and hang the piano wire for the second time. If the dummy shaft device is not concentric with the bottom ring seal ring, only need to adjust the center adjustment bolt of the dummy shaft device to adjust the center column of the dummy shaft device to be concentric with the bottom ring seal ring; if the center of the stator circle measuring frame does not meet the requirements of the unit center value, only need to move the circle measuring frame to make the center of the circle measuring frame located on the unit center. This avoids the secondary circular adjustment of the stator in the pit and the local extrusion deformation of the stator caused during the secondary circular adjustment process, reducing the construction time and improving the installation accuracy at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a schematic diagram of the positioning detection layout of the present invention;

[0031] Figure 2 is a schematic diagram of the dummy shaft device of the present invention;

[0032] Figure 3 is a schematic diagram of the layout of the central measurement points.

[0033] In the figure, 1 is the stator circle measuring frame, 1.1 is the center column of the circle measuring frame, 5 is the bottom ring seal ring, 6 is the dummy shaft device, 6.1 is the center column of the dummy shaft, 6.2 is the fixed seat, 6.3 is the shaft holding, 6.4 is the shaft holding adjustment bolt, 6.5 is the horizontal adjustment bolt, 6.6 is the base seat, 6.7 is the base, 6.8 is the fastening bolt, 6.9 is the adjustment bracket, 6.10 is the center of gravity adjustment bolt, 7 is the piano wire, 8 is the oil barrel, 9 is the weight, A is the horizontal distance from the piano wire to the upper end of the center column of the circle measuring frame, B is the horizontal distance from the piano wire to the lower end of the center column of the circle measuring frame, C is the horizontal distance from the piano wire to the upper end of the dummy shaft device, D is the horizontal distance from the piano wire to the lower end of the dummy shaft device, E is the horizontal distance from the upper end of the dummy shaft device to the upper part of the bottom ring seal ring, F is the horizontal distance from the lower end of the dummy shaft device to the lower part of the bottom ring seal ring, and X and Y are the axial directions of the plane positioning. Detailed implementation manners

[0034] The present invention will be further described below in conjunction with the detailed implementation manners. The detailed implementation manners are further explanations of the principle of the present invention and do not limit the present invention in any way. The same or similar technologies to the present invention do not exceed the scope of protection of the present invention.

[0035] In conjunction with the accompanying drawings.

[0036] As Figures 1 to 3 shown, the present invention includes a stator circle measuring frame 1 and a dummy shaft device 6. The stator circle measuring frame 1 is arranged on the circle measuring frame foundation platform in the pit.

[0037] In conjunction with Figure 1 and Figure 2 , the dummy shaft device 6 is a precision machined part, including a precision machined center column 6.1 of the dummy shaft, a base 6.7 and a fixed seat 6.2 for fixing the center column 6.1 of the dummy shaft, a shaft holding 6.3 and a shaft holding adjustment bolt 6.4 for adjusting the verticality of the dummy shaft. The base 6.7 and the fixed seat 6.2 are welded into a whole and fixed on the base seat 6.6, and are fixed by the fastening bolt 6.8, and the levelness (i.e., the verticality of the dummy shaft) can be adjusted by the horizontal adjustment bolt 6.5, and the center position of the center column 6.1 of the dummy shaft can be adjusted by the center of gravity adjustment bolt 6.10 and the adjustment bracket 6.9.

[0038] The method for positioning the center of the generator stator pit construction of the present invention includes the following steps:

[0039] 1) Checking and positioning the concentricity between the dummy shaft device 6 and the bottom ring seal ring 5:

[0040] ① The dummy shaft device 6 is arranged on the foundation ring and supported by a truss. The precision machined surface of the center column 6.1 of the dummy shaft device 6 is at the same elevation as the bottom ring seal ring 5.

[0041] ② Use a frame level to measure the perpendicularity in four directions of the false shaft center column 6.1, and roughly adjust the perpendicularity of the false shaft center column 6.1 ≤ 0.02 mm / m;

[0042] ③ Use an internal micrometer to measure the distances E and F between the false shaft center column 6.1 through the upper and lower rings of the bottom ring leakage stop ring 5:

[0043] On the same toroidal surface, check that the center deviation of the two corresponding measuring points in the X direction ≤ 0.05 mm, the center deviation of the two corresponding measuring points in the Y direction ≤ 0.05 mm, and the combined center deviation value in the X and Y directions is also ≤ 0.05 mm, which indicates that the false shaft center column 6.1 is located on the unit center; if the requirements are not met, the false shaft device 6 needs to be moved to adjust the false shaft center column 6.1 so that its center is located on the unit center.

[0044] On the same vertical surface, check the two corresponding measuring points in the X direction and the difference between their corresponding E and F values, and precisely adjust the perpendicularity of the false shaft center column 6.1, with its deviation ≤ 0.02 mm, which indicates that the false shaft center column 6.1 is vertical; if the requirements are not met, the false shaft center column 6.1 needs to be adjusted to be vertical by adjusting the horizontal adjustment bolt 6.5 of the false shaft device 6.

[0045] 2) Concentricity checking and positioning of the false shaft device 6 and the stator measuring circle frame 1:

[0046] ④ Install four piano wires 7 in the four measuring point directions of the X-axis and Y-axis outside the stator center column 1.1. Connect the lower ends of the piano wires 7 to the plumb bobs 9, and place the plumb bobs 9 into the oil drum 8;

[0047] ⑤ Measure the distances A, B, C, and D from the stator center column 1.1 and the false shaft center column 6.1 to the piano wires 7 respectively, and use the electrical measurement method to measure the concentricity of the stator center column 1.1 and the false shaft center column 6.1 through the external coaxiality measurement method:

[0048] On the same vertical surface, check the two corresponding measuring points in the X direction and the difference between their corresponding A and B values, and adjust the perpendicularity of the stator center column 1.1, with its deviation ≤ 0.02 mm, which indicates that the center column of the stator measuring circle frame 1 is vertical; if the requirements are not met, it needs to be adjusted to be vertical by adjusting the horizontal adjustment bolt of the stator measuring circle frame 1.

[0049] On the same toroidal surface, check the relative deviation values of the corresponding points of A, B, C, and D of the two measuring points in the X direction, calculate the center deviation value ≤ 0.05 mm, and check the relative deviation values of the corresponding points of A, B, C, and D of the two measuring points in the Y direction, calculate the center deviation ≤ 0.05 mm, which indicates that the stator center column 1.1 is located on the unit center; if the requirements are not met, the stator measuring circle frame 1 needs to be adjusted so that the center of the stator center column 1.1 is located on the unit center.

[0050] The above-mentioned "electrical measurement method" is a measurement method in the prior art, which means that the positive pole of the power supply is connected to the circle measuring frame through a wire and is in series with the earphone, and the negative pole is connected to the piano wire through a wire. There is no connection between the piano wire (the part of the wire rack for hanging the piano wire is insulated) and the central column of the circle measuring frame. That is, the earphone, the piano wire, and the central column of the circle measuring frame form an open series circuit. The distance from the piano wire to the central column of the circle measuring frame is measured by an internal diameter micrometer (a conductor). When the internal diameter micrometer contacts the piano wire and the central column of the circle measuring frame during measurement, a circuit is formed, that is, the earphone, the piano wire, the circle measuring frame, and the internal diameter micrometer form a connected series circuit, and the sound heard in the earphone is the sound of the short-circuit current. Whether the distance from the piano wire to the central column is the minimum distance is judged according to the size of the sound.

[0051] Figure 3 It is a schematic diagram of the layout of the central measurement points. As shown in the figure, when performing: 1) concentricity verification and positioning of the dummy shaft device 6 and the bottom ring seal ring 5, and 2) concentricity verification and positioning of the dummy shaft device 6 and the stator circle measuring frame 1, each measurement point is arranged at four symmetric points on the circumference along the X-axis and the Y-axis.

Claims

1. A construction center positioning device for a generator stator pit. A bottom ring water stop ring is arranged at the bottom of the generator stator pit, and a stator circularity measuring frame is arranged above the pit. The stator circularity measuring frame includes a central column of the circularity measuring frame, and is characterized in that: A dummy shaft device is arranged at the center of the bottom of the machine pit. The dummy shaft device includes a dummy shaft central column that can adjust the verticality and horizontal center position. The dummy shaft central column and the central column of the circumferential measuring frame are on the same vertical line at the center of the generator stator machine pit.

2. The center positioning device for the construction of the generator stator pit according to claim 1, characterized in that The dummy shaft device includes: a dummy shaft central column, a base and a fixing seat for fixing the dummy shaft central column, a shaft holding and shaft holding adjustment bolt for adjusting the verticality of the dummy shaft. The base and the fixing seat are welded into a whole and fixed on the foundation seat. The base adjusts the horizontal state through a horizontal adjustment bolt, adjusts the center position through at least two groups of gravity center adjustment bolts and adjustment brackets, and is fixed through a fastening bolt.

3. The center positioning device for the construction of the generator stator pit according to claim 2, characterized in that: Each group of gravity center adjustment bolts and adjustment brackets are arranged on the foundation seat and symmetrically arranged along the circumference of the base; the adjustment brackets are welded and fixed on the foundation seat, and the top of the gravity center adjustment bolt is in adjustable contact with the circumferential wall of the base.

4. The generator stator pit construction center positioning device according to claim 3, characterized in that: The fastening bolt is arranged on one side of the base to connect and fix the base to the foundation seat. A horizontal adjustment bolt with its top contacting the surface of the foundation seat is arranged on the base plane symmetric to the fastening bolt.

5. The generator stator pit construction center positioning device according to claim 3, characterized in that: The foundation seat is fixed on the structural body at the bottom of the machine pit.

6. A method for detecting the center positioning of a generator stator pit construction, characterized in that: Adopting the positioning device described in any one of claims 1 to 5, it includes the following steps: 1) Concentricity verification and positioning of the dummy shaft device and the bottom ring water stop ring: ① The dummy shaft device is arranged on the center foundation ring at the bottom of the machine pit, and the dummy shaft central column of the dummy shaft device is at the same elevation as the bottom ring water stop ring; ② Use a frame level to measure the verticality in the four directions of the X-axis and Y-axis of the dummy shaft central column, and roughly adjust the verticality of the dummy shaft central column ≤ 0.02 mm / m; ③ Use an internal diameter micrometer to measure the distances E and F between the dummy shaft central column and the upper and lower rings of the bottom ring water stop ring through the upper and lower rings of the bottom ring water stop ring; On the same ring surface, check that the center deviation of the two corresponding measuring points in the X direction ≤ 0.05 mm, the center deviation of the two corresponding measuring points in the Y direction ≤ 0.05 mm, and the combined center deviation value in the X and Y directions is also ≤ 0.05 mm, which indicates that the dummy shaft central column is located at the center of the unit; if the requirements are not met, move the dummy shaft device to adjust the dummy shaft central column so that its center is located at the center of the unit; On the same vertical surface, check the two corresponding measuring points in the X direction and the difference between the corresponding E and F, and precisely adjust the verticality of the dummy shaft central column, with its deviation ≤ 0.02 mm, which indicates that the dummy shaft central column is vertical; if the requirements are not met, adjust the verticality of the dummy shaft central column by adjusting the horizontal adjustment bolt of the dummy shaft device; 2) Concentricity verification and positioning of the dummy shaft device and the stator circumferential measuring frame: ④ Along the four measuring point directions of the X-axis and Y-axis on the outside of the stator central column, set up four piano wires. The lower ends of the piano wires are connected to plumb bobs, and the plumb bobs are placed in oil drums; ⑤ Measure the distances A, B, C, and D from the stator central column and the dummy shaft central column to the piano wires at each measuring point respectively, and use the electrical measurement method to measure the concentricity of the stator central column and the dummy shaft central column through the method of external measurement of coaxiality: On the same vertical surface, check the two corresponding measuring points in the X direction and the difference between the corresponding A and B, and adjust the verticality of the stator central column, with its deviation ≤ 0.02 mm, which indicates that the central column of the stator circumferential measuring frame is vertical; If the requirements are not met, it is necessary to adjust and make it vertical by adjusting the horizontal adjustment bolt of the stator circumferential measuring frame; On the same torus, check the relative deviation values of the corresponding points A, B, C, and D of the two measuring points in the X direction, calculate the central deviation value ≤ 0.05 mm, check the relative deviation values of the corresponding points A, B, C, and D of the two measuring points in the Y direction, calculate the central deviation ≤ 0.05 mm, then it indicates that the stator central column is located on the unit center; if the requirements are not met, it is necessary to adjust the stator circle measuring frame so that the center of the stator central column is located on the unit center.

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