A measurement and calculation method for the parallelism of a three-pad tilting pad bearing

Abstract

The present invention belongs to the technical field of equipment maintenance in nuclear power plants, and specifically relates to a method for measuring and calculating the parallelism of a three-pad tilting pad bearing, including Step 1, measuring the distance from the outer edge of the bearing body to the rotor; Step 2, calculating the correction coefficient of the distance from the outer edge of the bearing body to the rotor; Step 3, calculating the correction value of the distance from the rotor to the outer edge of the bearing body; Step 4, calculating the parallelism of the bearings in different directions; According to the method of the present invention, by correcting the distance values from the outer edges of the inner and outer bearing bodies to the generator rotor, the influence of the machining error of the outer diameters of the inner and outer bearing bodies on the measurement of the bearing parallelism can be eliminated, making the measurement and calculation of the bearing parallelism more accurate and ensuring that the design requirements are met. According to the method of the present invention, it has been applied to the maintenance work of the tilting pad bearings of the generators of Units 1-4 of a certain million-kilowatt-class pressurized water reactor power station for many times, completely solving the defect of large temperature difference between the bearing shells caused by the low measurement accuracy of the traditional method, achieving good results and improving the operating reliability of the generator.

Description

Technical Field

[0001] The present invention belongs to the technical field of nuclear power plant equipment maintenance, and particularly relates to a method for measuring and calculating the parallelism of a three-pad tilting pad bearing. Background Art

[0002] In a million-kilowatt nuclear power plant, the generator, as an important equipment in the secondary circuit, is responsible for converting the mechanical energy transmitted by the steam turbine into electrical energy and transmitting it to the power grid. The 1-4 units of a certain nuclear power plant adopt TA1100-78 type large four-pole half-speed synchronous generators, which mainly consist of components such as stator windings, iron cores, rotors, end covers, and tilting pad bearings. The generator rotor is supported by 2 three-pad tilting pad bearings. This type of bearing mainly consists of 1 bearing body (1), side pads (2), bottom pads (3), and top pads (4). For the specific structure, see Figure 1 , and two temperature sensors are provided along the axial direction of the bottom pad (3) for monitoring the operating temperature of the bearing bush. The outer edge of the bearing body is a cylindrical surface for measuring the parallelism between the bearing and the rotor.

[0003] There are parallelism requirements in the design between the generator bearing and the generator rotor, that is, the rotor center line should be parallel to both the vertical center line and the horizontal center line of the bearing. If the parallelism is unqualified, the contact between the generator rotor and the bearing pads is uneven, which easily causes uneven cooling effects of the pads, local overheating and even wear of the pads. At the same time, it causes a difference in the readings of the two pad metal temperature sensors on the bottom pad, that is, a large temperature difference in the generator bearing. The temperature difference of the generator bearing is an important monitoring parameter for the operation of the unit. Once it reaches the shutdown limit, shutdown treatment is required. Therefore, during the major overhaul of the power plant, it is necessary to measure the parallelism of the generator bearing and adjust it to the design range to ensure the installation quality of the generator bearing and the safe operation of the unit.

[0004] The conventional method for measuring the parallelism of the generator bearing is to measure the distance values from the outer edges of the inner and outer (the side close to the generator is the inner side of the bearing, and the side far from the generator is the outer side of the bearing, the same below) bearing bodies to the generator rotor in the vertical and horizontal directions respectively, and directly subtract them to obtain the parallelism in the vertical and horizontal directions. If it is unqualified, the parallelism is adjusted by using a jack to adjust the bearing position. Since the outer edge of the bearing body is a non-finished surface, there must be machining deviations in the diameters of the inner and outer bearing body outer edges during manufacturing. The conventional method does not consider the influence of the diameter difference of the bearing body outer edge, and the measured bearing parallelism is not accurate. During the application process in a certain million-kilowatt nuclear power plant, problems such as large temperature differences in the generator bearing bush caused by unqualified parallelism of the generator bearing have occurred, reducing the equipment reliability of the generator and affecting the safe and reliable operation of the system and the unit.

[0005] Therefore, inventing a more reliable parallelism measurement and calculation method for a three-pad tilting pad bearing is crucial for the safe and reliable operation of equipment and units. Summary of the Invention

[0006] In view of the above deficiencies, the object of the present invention is to provide a measurement and calculation method for the parallelism of a three-pad tilting pad bearing, aiming to accurately measure and calculate the parallelism of the tilting pad bearing of a generator to ensure meeting the design requirements.

[0007] The technical solution of the present invention is as follows:

[0008] A measurement and calculation method for the parallelism of a three-pad tilting pad bearing specifically includes the following steps. Step 1: Measure the distance from the outer edge of the bearing to the rotor; Step 2: Calculate the correction coefficient of the distance from the outer edge of the bearing to the rotor; Step 3: Calculate the correction value of the distance from the rotor to the outer edge of the bearing; Step 4: Calculate the parallelism of the bearing in different directions.

[0009] Step 1: Measure the distance from the outer edge of the bearing to the rotor;

[0010] In the vertical direction, that is, at the position of the top pad, use a special depth micrometer to measure the distance values from the outer edges of the inner and outer bearings to the rotor respectively. The inner distance value and the outer distance value are denoted as A1 and A2 respectively;

[0011] In the horizontal direction, that is, at the position of the side pad, use a special depth micrometer to measure the distance values from the outer edges of the inner and outer bearings to the rotor respectively. The inner distance value and the outer distance value are denoted as B1 and B2 respectively.

[0012] The said Step 2: Calculate the correction coefficient of the distance from the outer edge of the bearing to the rotor;

[0013] Use an outside micrometer to measure the diameters of the outer edges of the inner and outer bearings respectively. The inner diameter and the outer diameter are denoted as ΦD a 、ΦD b ;

[0014] Calculate the correction coefficient of the distance from the outer edge of the bearing to the rotor, that is, half of the difference between the diameters of the outer edges of the inner and outer bearings, denoted as d, that is

[0015] The said Step 3: Calculate the correction value of the distance from the rotor to the outer edge of the bearing;

[0016] If ΦD a >ΦD b , that is, the maximum value of the outer edge diameter of the bearing is on the inner side, then use the inner distance value from the outer edge of the bearing to the rotor as the calculation basis. The inner distance correction values from the outer edge of the bearing to the rotor in the vertical direction and the horizontal direction are denoted as A′1 and B′1 respectively. Then A′1 = A1 - d, B′1 = B1 - d.

[0017] Step 3: Calculate the correction value of the distance from the rotor to the outer edge of the bearing body;

[0018] If ΦD a <ΦD b , that is, the maximum value of the outer diameter of the bearing body is on the outside, then use the distance value from the outer edge of the bearing body to the rotor as the calculation basis. The correction values of the distance from the outer edge of the bearing body to the rotor in the vertical and horizontal directions are respectively denoted as A'2 and B'2, then A'2 = A2 - d, B'2 = B2 - d.

[0019] Step 4: Calculate the bearing parallelism in different directions;

[0020] Assume that the bearing parallelism in the vertical direction is denoted as △1, and the bearing parallelism in the horizontal direction is denoted as △2, then:

[0021] If ΦD a >ΦD b , then △1 = A2 - A'1, △2 = B2 - B'1;

[0022] If ΦD a <ΦD b , then △1 = A1 - A'2, △2 = B1 - B'2;

[0023] Both △1 and △2 should meet the requirements of [-0.02 mm, +0.02 mm]. If the value of △1 or △2 is not within this range, it means that there is a deviation in the relative position between the bearing bush and the shaft;

[0024] Therefore, it is necessary to adjust the bearing body 1. Gently jack up the rotor with a jack to raise the rotor journal so that there is a clearance between the rotor and the bearing bush, and then use the jack to adjust the position of the bearing body until both △1 and △2 are within the required range.

[0025] The beneficial effects of the present invention are as follows:

[0026] 1. According to the method of the present invention, by correcting the distance values from the inner and outer edges of the bearing body to the generator rotor, the influence of the machining error of the inner and outer diameters of the bearing body on the measurement of bearing parallelism can be eliminated, making the measurement and calculation of bearing parallelism more accurate and ensuring that the design requirements are met.

[0027] 2. According to the method of the present invention, it has been applied to the overhaul of the tilting pad bearings of the generators of Units 1 - 4 of a certain million - kilowatt - level pressurized water reactor power station for many times, completely solving the defect of large bearing bush temperature difference caused by the low measurement accuracy of the traditional method, achieving good results, and improving the operation reliability of the generator. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic structural diagram of the tilting pad bearing of the present invention;

[0029] Figure 2 It is a schematic diagram for the adjustment and measurement of the parallelism of a tilting pad bearing;

[0030] In the figure: 1 - bearing body; 2 - side pad; 3 - bottom pad; 4 - top pad. Specific implementation manner

[0031] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0032] All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0033] This solution designs a measurement and calculation method for the parallelism of a three-pad tilting pad bearing, which specifically includes the following steps:

[0034] Step 1: Measure the distance from the outer edge of the bearing body to the rotor;

[0035] Refer to Figure 2 , in the vertical direction, that is, at the position of the top pad 4, use a special depth micrometer to measure the distance values from the outer edges of the inner and outer bearing bodies 1 to the rotor respectively. The inner distance value and the outer distance value are denoted as A1 and A2 respectively.

[0036] Refer to Figure 2 , in the horizontal direction, that is, at the position of the side pad 2, use a special depth micrometer to measure the distance values from the outer edges of the inner and outer bearing bodies 1 to the rotor respectively. The inner distance value and the outer distance value are denoted as B1 and B2 respectively.

[0037] Step 2: Calculate the correction coefficient of the distance from the outer edge of the bearing body to the rotor;

[0038] Refer to Figure 2 , use an outside diameter micrometer to measure the diameters of the outer edges of the inner and outer bearing bodies 1 respectively. The inner diameter and the outer diameter are denoted as ΦD a 、ΦD b .

[0039] Calculate the correction coefficient of the distance from the outer edge of the bearing body 1 to the rotor, that is, half of the difference between the outer diameters of the inner and outer bearing bodies, denoted as d, that is

[0040] Step 3: Calculate the correction value of the distance from the rotor to the outer edge of the bearing body;

[0041] If ΦD a >ΦD b, that is, when the maximum value of the outer diameter of the bearing body is on the inner side, the distance value from the outer edge of the bearing body to the inner side of the rotor is used as the calculation basis. The correction values of the distance from the outer edge of the bearing body to the inner side of the rotor in the vertical and horizontal directions are denoted as A'1 and B'1 respectively. Then A'1 = A1 - d, B'1 = B1 - d;

[0042] If ΦD a <ΦD b , that is, when the maximum value of the outer diameter of the bearing body is on the outer side, the distance value from the outer edge of the bearing body to the outer side of the rotor is used as the calculation basis. The correction values of the distance from the outer edge of the bearing body to the outer side of the rotor in the vertical and horizontal directions are denoted as A'2 and B'2 respectively. Then A'2 = A2 - d, B'2 = B2 - d.

[0043] Step Four: Calculate the bearing parallelism in different directions;

[0044] Assume that the bearing parallelism in the vertical direction is denoted as △1, and the bearing parallelism in the horizontal direction is denoted as △2. Then:

[0045] If ΦD a >ΦD b , then △1 = A2 - A'1, △2 = B2 - B'1;

[0046] If ΦD a <ΦD b , then △1 = A1 - A'2, △2 = B1 - B'2;

[0047] Both △1 and △2 should meet the requirements of [-0.02mm, +0.02mm]. If the value of △1 or △2 is not within this range, it means that there is a deviation in the relative position between the bearing bush and the shaft.

[0048] Therefore, it is necessary to adjust the bearing body 1. Gently jack up the rotor with a jack to raise the rotor journal by a certain distance so that there is a gap between the rotor and the bearing bush. Then use the jack to adjust the position of the bearing body 1 until both △1 and △2 are within the required range.

[0049] In Steps One to Four, the upper and lower halves of the tilting pad bearing of the generator should be in the installed state.

[0050] In Steps One to Four, the side close to the generator is the inner side of the bearing, and the side far from the generator is the outer side of the bearing.

[0051] In Step Four, the bearing parallelism is further divided into vertical direction parallelism and horizontal direction parallelism. △1 represents the vertical direction parallelism, and △2 represents the horizontal direction parallelism.

[0052] (I) Measurement and calculation of bearing parallelism before repair

[0053] Step One: Measure the distance from the outer edge of the bearing body to the rotor

[0054] Reference Figure 2 At the vertical direction (i.e., at the position of the top pad 4), use a special depth micrometer to measure the distances from the outer edges of the inner and outer bearing bodies 1 to the rotor respectively. The inner distance value and the outer distance value are recorded as A1 = 341.66 mm and A2 = 341.82 mm respectively.

[0055] Reference Figure 2 At the horizontal direction (i.e., at the position of the side pad 2), use a special depth micrometer to measure the distances from the outer edges of the inner and outer bearing bodies 1 to the rotor respectively. The inner distance value and the outer distance value are recorded as B1 = 341.78 mm and B2 = 341.88 mm respectively.

[0056] Step 2: Calculate the correction coefficient of the distance from the outer edge of the bearing body to the rotor

[0057] Reference Figure 2 Use an outside micrometer to measure the diameters of the outer edges of the inner and outer bearing bodies 1 respectively. The inner diameter and the outer diameter are recorded as 1475.01 mm and 1474.99 mm respectively.

[0058] Calculate the correction coefficient of the distance from the outer edge of the bearing body 1 to the rotor, that is, half of the difference between the outer diameters of the inner and outer bearing bodies, denoted as d, that is

[0059] Step 3: Calculate the correction value of the distance from the rotor to the outer edge of the bearing body

[0060] Because ΦD a > ΦD b That is, the maximum value of the outer diameter of the bearing body is on the inner side. Then, based on the inner distance value from the outer edge of the bearing body to the rotor, the inner distance correction values from the outer edge of the bearing body to the rotor in the vertical and horizontal directions are denoted as A′1 and B′1 respectively. Then A′1 = A1 - d = 341.66 mm - 0.01 mm = 341.65 mm, B′1 = B1 - d = 341.78 mm - 0.01 mm = 341.77 mm.

[0061] Step 4: Calculate the bearing parallelism in different directions

[0062] Assume that the bearing parallelism in the vertical direction is denoted as △1, and the bearing parallelism in the horizontal direction is denoted as △2. Then:

[0063] Because ΦD a > ΦD b Then △1 = A2 - A′1 = 341.82 mm - 341.65 mm = 0.17 mm, △2 = B2 - B′1 = 341.88 mm - 341.77 mm = 0.11 mm;

[0064] Neither △1 nor △2 meets the requirement of [-0.02mm, +0.02mm], and the bearing parallelism is unqualified, indicating that there is a deviation in the relative position between the bearing bush and the shaft. Use a jack to adjust the position of the bearing body 1, and the measurement and calculation after adjustment are as follows.

[0065] (2) Measurement and calculation of bearing parallelism after repair

[0066] Step 1: Measure the distance from the outer edge of the bearing body to the rotor

[0067] Reference Figure 2 , in the vertical direction (i.e., at the position of the top pad 4), use a special depth micrometer to measure the distance values from the outer edges of the inner and outer bearing bodies 1 to the rotor respectively. The inner distance value and the outer distance value are recorded as A1 = 341.75mm and A2 = 341.73mm respectively.

[0068] Reference Figure 2 , in the horizontal direction (i.e., at the position of the side pad 2), use a special depth micrometer to measure the distance values from the outer edges of the inner and outer bearing bodies 1 to the rotor respectively. The inner distance value and the outer distance value are recorded as B1 = 341.90mm and B2 = 341.90mm respectively.

[0069] Step 2: Calculate the correction coefficient of the distance from the outer edge of the bearing body to the rotor

[0070] Reference Figure 2 , use an outside micrometer to measure the diameters of the outer edges of the inner and outer bearing bodies 1 respectively. The inner diameter and the outer diameter are recorded as 1475.01mm and 1474.99mm respectively.

[0071] Calculate the correction coefficient of the distance from the outer edge of the bearing body 1 to the rotor, that is, half of the difference between the outer diameters of the inner and outer bearing bodies, denoted as d, that is

[0072] Step 3: Calculate the correction value of the distance from the rotor to the outer edge of the bearing body

[0073] Because ΦD a > ΦD b , that is, the maximum value of the outer diameter of the bearing body is on the inner side, then use the inner distance value from the outer edge of the bearing body to the rotor as the calculation basis. The inner distance correction values from the outer edge of the bearing body to the rotor in the vertical direction and the horizontal direction are denoted as A′1 and B′1 respectively. Then A′1 = A1 - d = 341.75mm - 0.01mm = 341.74mm, B′1 = B1 - d = 341.90mm - 0.01mm = 341.89mm.

[0074] Step 4: Calculate the bearing parallelism in different directions

[0075] Assume that the bearing parallelism in the vertical direction is denoted as △1, and the bearing parallelism in the horizontal direction is denoted as △2, then:

[0076] Since ΦD a > ΦD b then Δ1 = A2 - A'1 = 341.73 mm - 341.74 mm = -0.01 mm, Δ2 = B2 - B'1 = 341.90 mm - 341.89 mm = 0.01 mm;

[0077] Both Δ1 and Δ2 meet the requirements of [-0.02 mm, +0.02 mm], and the bearing parallelism is qualified.

[0078] It should be noted that in the description of the present invention, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. In addition, in the description of the present invention, unless otherwise specified, the meaning of "a plurality" refers to at least two.

[0079] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0080] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

[0081] In the accompanying drawings of the disclosed embodiments of the present invention, only the methods related to the disclosed embodiments are involved. Other methods can refer to the usual designs. Without conflict, the same and different embodiments of the present invention can be combined with each other;

[0082] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A measurement and calculation method for the parallelism of a three-pad tilting pad bearing, specifically including the following steps: Step 1, measure the distance from the outer edge of the bearing body to the rotor; Step 2, calculate the correction coefficient of the distance from the outer edge of the bearing body to the rotor; Step 3, calculate the correction value of the distance from the rotor to the outer edge of the bearing body; Step 4, calculate the bearing parallelism in different directions. It is characterized in that: Step 1, measure the distance from the outer edge of the bearing body to the rotor; In the vertical direction, that is, at the position of the top pad, use a special depth micrometer to measure the distance values from the outer edges of the inner and outer bearing bodies to the rotor respectively. The inner distance value and the outer distance value are recorded as A1 and A2 respectively; In the horizontal direction, that is, at the position of the side pad, use a special depth micrometer to measure the distance values from the outer edges of the inner and outer bearing bodies to the rotor respectively. The inner distance value and the outer distance value are recorded as B1 and B2 respectively; The above-mentioned Step 2, calculate the correction coefficient of the distance from the outer edge of the bearing body to the rotor; Use an outside micrometer to measure the diameters of the outer edges of the inner and outer bearing bodies respectively. Denote the inner diameter and the outer diameter as ΦD a and ΦD b ; Calculate the correction coefficient of the distance from the outer edge of the bearing to the rotor, which is half of the difference in the outer diameter of the inner and outer bearing bodies, denoted as d, that is The above-mentioned Step 3, calculate the correction value of the distance from the rotor to the outer edge of the bearing body; If ΦD a >ΦD b , that is, if the maximum value of the outer diameter of the bearing body is on the inner side, the distance value from the outer edge of the bearing body to the inner side of the rotor is used as the calculation basis. The correction values of the distance from the outer edge of the bearing body to the inner side of the rotor in the vertical and horizontal directions are respectively denoted as A'1 and B'1, then A'1 = A1 - d, B'1 = B1 - d; The above-mentioned Step 3, calculate the correction value of the distance from the rotor to the outer edge of the bearing body; If ΦD a <ΦD b , that is, if the maximum value of the outer diameter of the bearing body is on the outside, then the distance value from the outer edge of the bearing body to the outside of the rotor is used as the calculation basis, and the correction values of the distances from the outer edge of the bearing body to the outside of the rotor in the vertical and horizontal directions are respectively denoted as A'2 and B'2, then A'2 = A2 - d, B'2 = B2 - d; The above-mentioned Step 4, calculate the bearing parallelism in different directions; Assume that the bearing parallelism in the vertical direction is recorded as Δ1, and the bearing parallelism in the horizontal direction is recorded as Δ2, then: If ΦD a > ΦD b , then Δ1 = A2 - A'1 and Δ2 = B2 - B'1; If ΦD a <ΦD b , then Δ1 = A1 - A'2, Δ2 = B1 - B'2; Both Δ1 and Δ2 should meet the requirements of [-0.02 mm, +0.02 mm]. If the value of Δ1 or Δ2 is not within this range, it means that there is a deviation in the relative position between the bearing bush and the shaft; Therefore, it is necessary to adjust the bearing body. Gently lift the rotor with a jack to raise the rotor journal so that there is a gap between the rotor and the bearing bush, and then use the jack to adjust the position of the bearing body until both Δ1 and Δ2 are within the required range.

2. The method for measuring and calculating the parallelism of a three-pad tilting pad bearing according to claim 1, characterized in that: Both the upper and lower halves of the tilting pad bearing should be in the installed state.

3. The method for measuring and calculating the parallelism of a three-pad tilting pad bearing according to claim 1, wherein: The side close to the generator is the inner side of the bearing, and the side far from the generator is the outer side of the bearing.

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